[Federal Register Volume 86, Number 5 (Friday, January 8, 2021)]
[Proposed Rules]
[Pages 1588-1634]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-29125]
[[Page 1587]]
Vol. 86
Friday,
No. 5
January 8, 2021
Part II
Department of Commerce
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National Oceanic and Atmospheric Administration
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50 CFR Part 217
Taking Marine Mammals Incidental to the Hampton Roads Bridge Tunnel
Expansion Project in Norfolk, Virginia; Proposed Rule
Federal Register / Vol. 86 , No. 5 / Friday, January 8, 2021 /
Proposed Rules
[[Page 1588]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Part 217
[Docket No. 201228-0360]
RIN 0648-BK21
Taking Marine Mammals Incidental to the Hampton Roads Bridge
Tunnel Expansion Project in Norfolk, Virginia
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Proposed rule; request for comments and information.
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SUMMARY: NMFS has received a request from the Hampton Roads Connector
Partners (HRCP) for authorization to take small numbers of marine
mammals incidental to pile driving and removal activities at the
Hampton Roads Bridge Tunnel Expansion Project (HRBT) in Norfolk,
Virginia over the course of five years (2021-2026). Pursuant to the
Marine Mammal Protection Act (MMPA), NMFS is proposing regulations to
govern that take, and requests comments on the proposed regulations.
NMFS will consider public comments prior to making any final decision
on the issuance of the requested MMPA authorization, and agency
responses will be summarized in the final notice of our decision.
DATES: Comments and information must be received no later than February
8, 2021.
ADDRESSES: You may submit comments, identified by NOAA-NMFS-2020-0164,
by the following method:
Comment submissions: Submit all public comments via the
Federal eRulemaking Portal, Go to www.regulations.gov/#!docketDetail;D=NOAA-NMFS-2020-0164, click the ``Comment Now!'' icon,
complete the required fields, and enter or attach your comments.
Instructions: Comments sent by any other method, to any other
address or individual, or received after the end of the comment period,
may not be considered by NMFS. All comments received are a part of the
public record and will generally be posted for public viewing on
www.regulations.gov without change. All personal identifying
information (e.g., name, address), confidential business information,
or otherwise sensitive information submitted voluntarily by the sender
will be publicly accessible. NMFS will accept anonymous comments (enter
``N/A'' in the required fields if you wish to remain anonymous).
Attachments to electronic comments will be accepted in Microsoft Word,
Excel, or Adobe PDF file formats only.
FOR FURTHER INFORMATION CONTACT: Robert Pauline, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Availability
A copy of HRCP's application and any supporting documents, as well
as a list of the references cited in this document, may be obtained
online at: https://www.fisheries.noaa.gov/action/incidental-take-authorization-hampton-roads-bridge-tunnel-expansion-project-hampton-0.
In case of problems accessing these documents, please call the contact
listed above (see FOR FURTHER INFORMATION CONTACT).
Purpose and Need for Regulatory Action
This proposed rule would establish a framework under the authority
of the MMPA (16 U.S.C. 1361 et seq.) to allow for the authorization of
take of marine mammals incidental to construction activities including
pile installation and pile replacement, as part of the (HRBT). The HRBT
is a major road transport infrastructure project conducted by HRCP
along the existing I-64 highway in Virginia, consisting of roadway
improvements, trestle bridges, and bored tunnels crossing the James
River between Norfolk and Hampton. The project will address severe
traffic congestion at the existing HRBT crossing by increasing traffic
capacity and upgrading lanes. We received an application from HRCP
requesting five-year regulations and authorization to take multiple
species of marine mammals. Take would occur by Level A and Level B
harassment only incidental to impact pile driving, vibratory pile
driving, vibratory pile removal, jetting, and down-the-hole (DTH) pile
installation. Please see Background below for definitions of
harassment.
Legal Authority for the Proposed Action
Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1371(a)(5)(A)) directs
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 for up to five years
if, after notice and public comment, the agency makes certain findings
and issues regulations that set forth permissible methods of taking
pursuant to that activity and other means of effecting the ``least
practicable adverse impact'' on the affected species or stocks and
their habitat (see the discussion below in the Proposed Mitigation
section), as well as monitoring and reporting requirements. Section
101(a)(5)(A) of the MMPA and the implementing regulations at 50 CFR
part 216, subpart I provide the legal basis for issuing this proposed
rule containing five-year regulations, and for any subsequent LOAs. As
directed by this legal authority, this proposed rule contains
mitigation, monitoring, and reporting requirements.
Summary of Major Provisions Within the Proposed Rule
Following is a summary of the major provisions of this proposed
rule regarding HRCP's construction activities. These measures include:
Shutdown of construction activities under certain
circumstances to avoid injury of marine mammals.
Required monitoring of the construction areas to detect
the presence of marine mammals before beginning construction
activities.
Soft start for impact pile driving to allow marine mammals
the opportunity to leave the area prior to initiating impact pile
driving at full power.
Use of bubble curtains during impact driving of steel
piles except when water depth is less than 20 feet.
Background
Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1361 et seq.) directs
the Secretary of Commerce (as delegated to NMFS) 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, regulations are issued, and notice is
provided to the public.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant), and if the permissible methods of taking and
requirements pertaining to the mitigation, monitoring and reporting of
the 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.
[[Page 1589]]
Except with respect to certain activities not pertinent here, the
MMPA defines ``harassment'' as: Any act of pursuit, torment, or
annoyance which (i) has the potential to injure a marine mammal or
marine mammal stock in the wild (Level A harassment); or (ii) has the
potential to disturb a marine mammal or marine mammal stock in the wild
by causing disruption of behavioral patterns, including, but not
limited to, migration, breathing, nursing, breeding, feeding, or
sheltering (Level B harassment).
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review the proposed action (i.e., the promulgation of
regulations and subsequent issuance of an incidental take
authorization) with respect to potential impacts on the human
environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (Incidental harassment authorizations
(IHAs) with no anticipated serious injury or mortality) of the
Companion Manual for NOAA Administrative Order 216-6A, which do not
individually or cumulatively have the potential for significant impacts
on the quality of the human environment and for which we have not
identified any extraordinary circumstances that would preclude this
categorical exclusion. Accordingly, NMFS has preliminarily determined
that the issuance of the proposed IHA qualifies to be categorically
excluded from further NEPA review.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
incidental take authorization request.
Summary of Request
On November 19, 2019, NMFS received an application from HRCP
requesting authorization for take of marine mammals incidental to
construction activities related to a major road transport
infrastructure project along the existing I-64 highway in Virginia,
consisting of roadway improvements, trestle bridges, and bored tunnels
crossing Hampton Roads between Norfolk and Hampton, Virginia. HRCP
submitted a revised LOA application on June 27, 2020 which included
changes to construction methods. We determined the application was
adequate and complete on September 29, 2020. On October 7, 2020 (85 FR
63256), we published a notice of receipt (NOR) of HRCP's application in
the Federal Register, requesting comments and information related to
the request for thirty days. No comments were received on the NOR.
HRCP requests authorization to take a small number of five species
of marine mammals by Level A and Level B harassment only. Neither HRCP
nor NMFS expects serious injury or mortality to result from this
activity. The proposed regulations would be valid for five years (2021-
2026). Note that HRCP had previously applied for an IHA to cover
initial in-water pile driving work. NMFS issued the IHA on July 10,
2020 (85 FR 48153; August 10, 2020).
Description of Proposed Activity
HRCP is proposing to conduct construction activities associated
with the HRBT project. This is a major road transport infrastructure
project along the existing I-64 highway in Virginia, consisting of
roadway improvements, trestle bridges, and bored tunnels crossing
Hampton Roads between Norfolk and Hampton. The Project will address
severe traffic congestion at the existing HRBT crossing by increasing
capacity. The Project will include widening I-64 to create an eight-
lane facility with a consistent six-lanes between the I-64/I-664 and I-
64/I-564 Interchange, which could expand to eight-lanes during peak
travel periods with the use of drivable shoulder lanes within the
Project limits. The Project will include the construction of two new
two-lane tunnels, expansion of the existing portal islands, and full
replacement of the existing North and South bridge-trestles.
The proposed HRBT project would include pile installation and pile
removal. Pile installation methods will include impact and vibratory
driving, jetting, and DTH pile installation. Pile removal techniques
for temporary piles will include vibratory pile removal or cutting
three feet below the mudline. Impact pile installation is projected to
take place at 3 to 4 locations simultaneously and there is the
potential for as many as 7 pile installation locations operating
concurrently with different hammer types. Pile installation and removal
can occur at variable rates, from a few minutes one day to several
hours the next. HRCP anticipates that between 1 to 10 piles could be
installed per day, depending on project scheduling.
The proposed action may incidentally expose marine mammals
occurring in the vicinity to elevated levels of underwater sound,
thereby resulting in incidental take, by Level A and Level B
harassment.
Dates and Duration
The proposed regulations would be valid for a period of five years
(2021-2026). The specified activities may occur at any time during the
five-year period of validity of the proposed regulations. HRCP expects
pile driving and removal to occur six days per week. The overall number
of anticipated days of pile installation and removal is 312 each year
for years 1-4 and 181 days for year 5, based on a 6-day work week. Over
five years this would result in an estimated total of 1,429 days of in-
water construction work, which may last from a few minutes up to
several hours per day.
HRCP plans to conduct work during daylight hours although pile
installation and removal may extend into evening or nighttime hours as
needed to accommodate pile installation requirements (e.g., once pile
driving begins, a pile will be driven to design tip elevation). In
order to maintain pile integrity and follow safety precautions, pile
installation or removal will continue after dark only for piles already
in the process of being installed or removed. Installation or removal
will not commence on new piles after dark.
Specific Geographic Region
The proposed project area is located in the waterway of Hampton
Roads adjacent to the existing bridge and island structures of the
HRBT. Hampton Roads is located at the confluence of the James River,
the Elizabeth River, the Nansemond River, Willoughby Bay, and the
Chesapeake Bay. Navigational channels are maintained by the U.S. Army
Corps of Engineers (USACE) within Hampton Roads to provide transit to
the many ports in the region. Maintained navigation channels near the
project area consist of:
Norfolk Harbor Entrance Reach (1,000 to 1,400 feet wide
and is maintained at a depth of 50 feet Mean Lower Low Water [MLLW]);
Hampton Creek Entrance Channel (200 feet wide and is
maintained at a depth of 12 feet MLLW);
Phoebus Channel (150 feet wide and is maintained at a
depth of 12 feet MLLW); and
Willoughby Channel (200 feet wide and is maintained at a
depth of 10 feet MLLW).
Sediments are mostly fine and medium sands with various amounts of
coarse sand and gravel, and low organic carbon content. There is no
naturally occurring rocky or cobble bottom present at or adjacent to
the project area. The North Shore in Hampton contains estuarine
intertidal sandy shore,
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estuarine intertidal reef, as well as submerged aquatic vegetation
(SAV) in shallow estuarine open water. The North Trestle is located in
estuarine open water with depths less than 15 feet below MLLW. The
North Island is surrounded by estuarine intertidal sandy shore and
rocky shore. Estuarine open water depths are primarily less than 15
feet below MLLW, but drop to approximately 25 feet below MLLW near the
southwest corner of the island expansion closer to the Hampton Creek
Entrance Channel. The South Island is also surrounded by estuarine
intertidal sandy shore and rocky shore, followed by estuarine open
water. The proposed island expansion is mainly in deep water (15 to 30
feet below MLLW), with a pocket of deeper water approximately 35 feet
below MLLW to the west. The South Trestle is primarily located in
estuarine open water with depths less than 15 feet below MLLW, with the
exception of deep water (15 to 30 feet below MLLW) near the South
Island approach. The north shore of Willoughby Bay contains estuarine
intertidal sandy shore with two small pockets of estuarine intertidal
emergent wetlands to the east. The Willoughby Bay Trestles are located
in estuarine open waters with depths of less than 15 feet below MLLW,
with the entire west bound trestle in water less than 6.6 feet below
MLLW. Willoughby Bay contains an estuarine intertidal sandy shore and
consists of estuarine open water with depths to 15 feet below MLLW.
A map of the HRBT Project Area is provided in Figure 1 below and
Figures 1-1 and 2-1 in HRCP's application.
BILLING CODE 3510-22-P
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[GRAPHIC] [TIFF OMITTED] TP08JA21.002
BILLING CODE 3510-22-C
The proposed project will widen I-64 for approximately 9.9 miles
along I-64 from Settlers Landing Road in Hampton, Virginia, to the I-
64/I-564 interchange in Norfolk, Virginia. The project will create an
eight-lane facility with six consistent use lanes and will include full
replacement of the North and South Trestle-Bridges, two new parallel
tunnels constructed using a tunnel boring machine (TBM), expansion of
the existing portal islands, and widening of the Willoughby Bay
Trestle-Bridges, Bay Avenue Bridges, and Oastes Creek Bridges. Also,
upland portions of I-64 will be widened to accommodate the additional
lanes, the Mallory Street Bridge will be replaced, and the I-64
overpass bridges will be improved.
Table 1--HRBT Expansion Project Design Segments
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Project design segment number and name Construction area
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Segment 1a (Hampton)........................ Area 1.
Segment 1b (North Trestle-Bridges) \1\...... Area 2.
Segment 2a (Tunnel) \1\..................... Area 3.
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Segment 3a (South Trestle-Bridge) \1\....... Area 2.
Segment 3b (Willoughby Spit) \1\............ Area 4.
Segment 3c (Willoughby Bay Trestle-Bridges) Area 2.
\1\.
Segment 3d (4th View Street Interchange).... Area 4.
Segment 4a (Norfolk-Navy)................... Area 4.
Segment 5a (I-564 Interchange).............. Area 4.
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\1\ Indicates segment includes in-water construction activities.
The proposed project design is divided into five segments as shown
in Table 1. However, only the sub-segments identified in Table 1 and
described below would include in-water marine construction activities
that have the potential to affect marine mammals:
Segment 1b--North Trestle-Bridges
This segment includes new and replacement north tunnel approach
trestles, This segment is located in Construction Area 2 as shown in
Figure 1 above and Figure 1-1 in HRCP's application.
Temporary Work Trestles for Bridge Construction at the North
Trestle--Several temporary work trestles will support construction of
the permanent eastbound and westbound North Trestle-Bridges. The
temporary North Shore Work Trestle will support construction of the
permanent eastbound North Trestle-Bridge in the shallow water (<4 to 6
feet Mean Low Water (MLW)) closer to the North Shore, avoiding the need
to dredge or deepen this area. The temporary North Shore Work Trestle
(194 36-inch steel pipe piles) will be installed under the 2020 IHA (85
FR 48153; August 10, 2020) and will be removed using a vibratory hammer
at the end of the project under this LOA (See Table 6). Unless stated
otherwise, all of the work described below will be conducted as part of
the proposed LOA.
Additional temporary work trestles will support construction of the
permanent westbound North Trestle-Bridge in the shallow water near the
North Island. These work trestles will be the same or similar to the
North Shore Work Trestle, steel structures founded on 36-inch diameter
steel pipe piles with 30 to 40 feet spans sized to accommodate a 300-
ton crane. Approximately 182 36-inch steel piles will be installed to
support these trestles using a combination of vibratory and impact
hammers except along the shoreline where drilling with a DTH hammer may
be needed to install piles through the armor stone.
Once that portion of the permanent eastbound and westbound North
Trestle-Bridge is complete, the temporary pile foundations will be
removed using a vibratory hammer and the work trestle reused for
similar purposes at a different location on the project (e.g.,
Willoughby Bay Work Trestles).
Jump Trestles for Bridge Construction at the North Trestle--Jump
Trestles are temporary heavy duty platforms used to support cranes and
other equipment, will be used the North Trestle for constructing
trestle bridges. Jump trestles are built with a maximum of three spans
which are progressively removed and reinstalled one span at a time,
moving forward with the construction of the adjacent structure. Each
span is supported by six (6) temporary 36-inch steel pipe piles. The
steel pipe piles will be installed, removed, and reinstalled as the
spans move forward using a combination of vibratory and impact hammers
for installation except along the shoreline where drilling with a DTH
hammer may be needed to install piles through the armor stone and
vibratory hammers will be used for removal. Approximately 270
individual pile installations and 270 removals will be needed to
support the Jump Trestle movement for construction of the permanent
westbound North Trestle-Bridge.
Templates and Permanent Piles at the North Trestle--Temporary
template piles will be used to guide installation of the permanent
concrete piles used to support the new North Trestle-Bridge (Table 7).
The templates will be supported by four temporary steel piles up to 36-
inch in diameter, generally one at each corner of the template. A two-
tier template will be used to account for the possible batter of the
permanent piles. Each template will allow installation of multiple
permanent concrete piles. A vibratory hammer will be used to install
and remove the temporary 36-inch steel piles supporting the template.
Five hundred and sixty-two (562) permanent 54-inch concrete
cylinder piles will be installed using an impact hammer and will remain
in place at the end of construction. Pre-drilling will be done in the
open without the use of a casing.
The drill, drill steel, and auger would be in leads and either
attached to the pile leads or used independently and indexed to the
template to resist rotation. The auger is anticipated to be 54-inch in
diameter and 10 feet or less in height.
In areas containing rock obstructions, a casing will be advanced
prior to installation of the permanent North Trestle piles. The DTH
hammer will advance a 60-inch (outer diameter) steel pipe pile casing
before installation of the 54-inch concrete cylinder pile.
Approximately 15 60-inch steel pipe casings may be required. The 60-
inch steel pipe casings will be left in place and cut to an appropriate
length to accommodate final island construction.
Demolition Trestle at the North Trestle--The North Trestle
Demolition Trestle will consist of a series of jump trestles, similar
to or the same as that used to construct the permanent westbound North
Trestle-Bridge. The jump trestles will be located in the shallow water
near the North Shore and will be installed, removed, and reinstalled as
demolition of the existing structures moves from the shoreline towards
deeper water. Each jump trestle used for demolition will be 45 feet
wide and approximately 1,200 feet long. Each jump trestle span will be
supported by temporary 36-inch steel pipe piles. Approximately 344
individual pile installations and 344 removals will be needed to
support the jump trestle movements using a combination of vibratory and
impact hammers for installation except along the shoreline where a DTH
hammer may be needed to install piles through the armor stone and
vibratory hammers will be used for removal.
Moorings at the North Shore Work Trestle--Mooring dolphins that
were installed under the existing IHA (85 FR 48153; August 10, 2020) at
the southern end and along the outside edge of the North Shore Work
Trestle will be removed as part of the LOA. Each dolphin consists of
three 24-inch steel piles (Table 6). An additional thirteen
[[Page 1593]]
(13) 42-inch steel pipe piles were installed along the outer edge of
the work trestle to provide additional single mooring points for barges
and vessels delivering material and accessing the trestle. The 24-inch
steel pipe piles and 42-inch steel pipe piles will be removed using a
vibratory hammer.
Sheet Piles at the North Shore Abutment--Approximately 187
temporary panels of steel sheet piles (AZ-700-19) will be installed
using a vibratory hammer at the North Shore shoreline to support
excavation and construction of the North Shore Abutment. Most of this
work is planned to be done at lower tides so that in-water work is
minimized. However, some installation work below the tidal elevations
(in-water) can be expected. Sheet piles will be removed using a
vibratory hammer.
Segment 2a--Tunnel
This segment includes new bored tunnels, the tunnel approach
structures, buildings, the North Island improvements for tunnel
facilities, and South Island improvements. This segment is located in
Construction Area 3 as shown in Figure 1.
Moorings at the North Island Expansion--Eighty (80) temporary
moorings were installed along the perimeter of the North Island
Expansion (North and South) under the existing IHA (HRCP 2020). All
moorings will be removed using a vibratory hammer or cut to
approximately 3 feet below the mudline.
Hampton Creek Approach Channel Marker at the North Island--An
existing pile-mounted (Aid to Navigation) channel marker at the
entrance to the Hampton Creek Approach Channel will be removed and
relocated to allow expansion of the North Island. It will be removed
using a vibratory hammer and a new permanent pile (36-inch steel pile)
will be installed using a vibratory hammer.
Steel sheet piles will be installed as part of the North Island
Expansion and at the shoreline of the North Island (Attachment 1,
Figure 9) to support excavation and construction of the North Island
Abutments and Expansion. Approximately 54 panels of sheet pile will be
installed using a vibratory hammer around the perimeter of the North
Island Expansion to support dredge and replacement of native soft
soils. An additional 122 sheet pile panels will be installed around the
perimeter of the North Island Expansion to support construction of the
abutment and tunnel approach structure.
Approximately 128 panels of sheet pile will be installed at the
North Island shoreline to support excavation and construction of the
North Island Abutment. Most of this work is expected to be done at
lower tides so that in-water work is minimized. However, some sheet
pile installation work below the tidal elevations (in-water) can be
expected. All sheet piles will be removed using a vibratory hammer.
TBM Platform at the South Island--HRCP is constructing the
temporary TBM Platform or ``quay'' at the South Island to allow for the
delivery, unloading, and assembly of the TBM components from barges to
the Island. The installation of the TBM platform will occur under the
existing IHA (HRCP 2020).
The TBM Platform is a steel structure erected on 216 36-inch
diameter steel piles, with an overall area of approximately 0.70 acre
(approximately 377 feet x 81 feet). The TBM Platform piles will be
removed using a vibratory hammer or cut to approximately 3 feet below
the mudline at the conclusion of the project.
Conveyor Trestle at the South Island--Tunnel boring spoils and
other related materials will be moved between the South Island and
barges via a conveyor belt and other equipment inside the tunnel
boring. The Conveyor Trestle will also be used for maintenance and
mooring of barges and vessels carrying TBM materials and other project-
related materials. The Conveyor Trestle will be erected on 84 36-inch
diameter steel piles. Installation of the Conveyor Trestle will occur
under the existing IHA (85 FR 48153; August 10, 2020). At the
conclusion of the project, the Conveyor Trestle piles will be removed
using a vibratory hammer or cut to approximately 3 feet below the
mudline.
Settlement Reduction Piles and Deep Foundation Piles at the South
Island--Existing geotechnical conditions at the planned South Island
Expansion will require additional considerations to reduce island
settlement and support roadway construction. Therefore, approximately
394 24-inch steel pipe settlement reduction piles and 507 30-inch
concrete-filled steel pipe deep foundation piles will be installed at
the South Island Expansion to address these geotechnical conditions.
The settlement reduction piles and the deep foundation piles will be
installed using vibratory and impact hammers. Furthermore, the use of
drilling with a DTH hammer may be needed to install the deep foundation
piles through the armor stone. Temporary templates (Table 7) will be
supported by four temporary steel pipe piles up to 36-inch in diameter
that will be spudded in place and used to align the piles during
installation. Steel sheet piles will be installed to partially enclose
the deep foundation piles as installation progresses north to south
along the island expansion area. For steel pipe piles in water depths
greater than 20 feet, a bubble curtain will be used for pile
installation to reduce hydroacoustic impacts caused by the impact
hammer. A portion of the settlement reduction piles and deep foundation
piles will be installed using a bubble curtain. See Mitigation for
additional detail.
Moorings at the South Island--Temporary moorings will be installed
along the perimeter of the South Island Expansion to support the
construction of the island expansion. Twenty-five (25) 42-inch steel
pipe piles will be installed to provide mooring points for barges and
vessels. The mooring point piles will be installed using a vibratory
hammer and eventually removed using a vibratory hammer.
Sheet Piles at the South Island Expansion and Abutment--Steel sheet
piles will be installed as part of the South Island Expansion and at
the shoreline of the South Island to support excavation and
construction of the South Island Abutment. Approximately 152 panels of
AZ-700-26 sheet pile will be installed around the perimeter of the
South Island Expansion deep foundation piles using a vibratory hammer
as pile installation progresses to support backfilling.
In addition, approximately 226 panels of AZ-700-26 temporary steel
sheet pile will be installed around the perimeter of the South Island
Expansion to support dredge and replacement of native soft soils.
Temporary steel sheet piles will be installed using a vibratory hammer
and will be removed using a vibratory hammer after completion of
dredging/replacement works.
Approximately 70 panels of AZ-700-19 sheet pile will be installed
at the South Island shoreline to support excavation and construction of
the abutment and tunnel approach structure at the South Island. Similar
to the North Shore Abutment work, most of this work is expected to be
done at lower tides so that in-water work is minimized. However, some
sheet pile installation work below the tidal elevations (in-water) can
be expected. All sheet piles will be removed using a vibratory hammer.
Segment 3a--South Trestle-Bridge
This segment includes the new South Trestle-Bridge and any bridge
elements that interface with the South Island to the south end of the
south abutments at Willoughby Spit. This segment is
[[Page 1594]]
located in Construction Area 2 as shown in Figure 1.
Moorings at the South Trestle--Temporary moorings will be installed
in the area of the South Trestle to support the construction of
temporary work trestles and permanent trestle bridges. The installation
of the moorings at the South Trestle will be performed under the
existing IHA (HRCP 2020). The temporary moorings will be removed at the
conclusion of the project using a vibratory hammer.
Temporary Work Trestles for Bridge Construction at the South
Trestle--Several temporary work trestles will support construction of
the temporary bridges used for maintaining traffic at the South Trestle
during construction (i.e., temporary MOT bridges) and will serve as
temporary docks for delivery of deck elements and other materials. The
South Trestle Work Trestles will consist of two separate structures at
the South Island shoreline (South Island South 1 and 2) and a third
structure at the South Shore or Norfolk shoreline.
The temporary South Trestle Work Trestle at South Island South 1 is
a steel structure approximately 504 feet long and 44 feet wide, founded
on 72 36-inch diameter steel piles with 30 to 40 feet spans sized to
accommodate a 300-ton crane. Once the permanent roadway is complete,
the temporary MOT Bridge will be removed as well as the South Island
South 1 Work Trestle, including the temporary pile foundations and
mooring piles. They will be removed via vibratory hammer and the work
trestle will be reused for similar purposes at a different project
location.
The temporary South Trestle Work Trestle at South Island South 2 is
a steel structure approximately 634 feet long and 54 feet wide, founded
on 90 36-inch diameter steel piles with 30 to 40 feet spans sized to
accommodate a 300-ton crane. The pile foundations will be removed using
a vibratory hammer once the permanent roadway is complete.
The temporary South Trestle Work Trestle at the South Shore or
Norfolk shoreline will be similar to that used elsewhere on the
project. The work trestle will be approximately 500 feet long and 66
feet wide with four 30 feet wide finger piers. The finger piers will
consist of 94 36-inch diameter steel piles installed using a vibratory
hammer.
Temporary steel pile foundations for each of the work trestles will
be installed using vibratory and impact hammers. A bubble curtain will
be used during installation of steel pipe piles in water depths greater
than 20 feet. Some areas near the shores and islands will require the
use of drilling with a DTH hammer to install the temporary piles. The
South Trestle Work Trestle pile foundations will be removed using a
vibratory hammer.
Templates and Permanent Piles at the South Trestle--Temporary
template piles (Table 7) will be used to guide installation of the
permanent concrete piles used to support the new South Trestle-Bridge.
The templates will use four temporary steel piles up to 36-inch in
diameter as supports, generally one at each corner of the template. A
two-tier template will be used to account for the possible batter of
the piles. Each template will allow installation of multiple permanent
concrete piles. A vibratory hammer will be used to install and remove
the temporary 36-inch steel piles supporting the template.
Eight hundred and ten (810) permanent 54-inch concrete cylinder
piles will be installed using an impact hammer and will remain in place
at the end of construction. Pre-drilling will be done in the open
without the use of a casing. The drill, drill steel, and drill auger
would be in leads and either attached to the pile leads or used
independently and indexed to the template to resist rotation. The drill
auger is anticipated to be 54-inch in diameter and 10-feet less in
height. It is expected that the drill, drill steel, and drill auger
would have almost no impact on noise levels.
In areas where there may be rock obstructions, such as at the toe
of the existing South Island slope, a casing will be advanced prior to
installation of the permanent South Trestle piles. The DTH hammer will
advance a 60-inch (outer diameter) steel pipe pile casing before
installation of the 54-inch concrete cylinder pile. Approximately 65
60-inch steel pipe casings may be required. The 60-inch steel pipe
casings will be left in place and cut to an appropriate length to
accommodate final island construction.
Jump Trestle for Bridge Construction at the South Trestle--
Temporary jump trestles will be used for constructing trestle bridges
(both new permanent and temporary MOT bridges) at the South Trestle. A
combination of jump trestles and working from the existing trestles
will be used to build the new trestle bridges.
The 36-inch steel pipe piles will be installed, removed, and
reinstalled as the spans move forward using a combination of vibratory
and impact hammers for installation except along the shoreline where
drilling with a DTH hammer may be needed to install piles through the
armor stone. Vibratory hammers will be used for removal. A bubble
curtain will be used for installation of steel pipe piles in water
depths greater than 20 feet. Approximately 420 individual pile
installations and 420 removals will be needed to support the jump
trestle movement for construction of the permanent westbound South
Trestle-Bridge.
Temporary MOT Trestles at the South Trestle--Two temporary MOT
Trestle bridges at the South Trestle will be used to phase construction
and carry traffic prior to completion of the new structures. The
eastbound traffic will be shifted on the new MOT Trestle to allow for a
partial demolition of the existing eastbound bridge-trestle. Once the
partial demolition is completed, the new eastbound connection to the
eight-lane trestle will be built with the support of a jump trestle and
eastbound traffic will be shifted on it. A temporary MOT Trestle will
be built from South Island next to the existing westbound trestle. The
westbound traffic will be shifted on the new MOT Trestle to allow for a
partial demolition of the existing westbound bridge-trestle. A portion
of the existing eastbound bridge-trestle will also be demolished to
allow the new connection between the eight-lane structure and the new
westbound bridge-trestle. The temporary MOT Trestle at the South
Trestle will be a steel structure erected on 218 36-inch steel pipe
piles that will be installed using a combination of vibratory and
impact hammers except along the shoreline where drilling with a DTH
hammer may be needed to install piles through the armor stone. A bubble
curtain will be used for installation of steel pipe piles in water
depths greater than 20 feet. Pile foundations will be removed using a
vibratory hammer.
Thirty 42-inch steel pipe pile casings will be installed using a
vibratory hammer in areas where the MOT trestle is in the footprint of
the South Island Expansion. The 42-inch steel pipe pile casings will be
left in place and cut to an appropriate length to accommodate final
island construction.
Demolition Trestle at the South Trestle--The South Trestle
Demolition Trestle will be similar to the work trestles previously
described (e.g. Demolition Trestle at the North Trestle). Located at
the South Shore, the South Trestle Demolition Trestle will be used to
access the shallow water at the South Shore and support equipment used
to remove the existing trestle structure. Approximately 72 36-inch
steel pipe piles will be installed with a combination of vibratory and
impact hammers. Some areas near the shores and islands will require the
use of a DTH hammer to install the temporary
[[Page 1595]]
piles. At the conclusion of the project, the South Trestle Demolition
Trestle will be removed using a vibratory hammer.
Segment 3C--Willoughby Bay Trestle-Bridges
This segment includes the new South Trestle-Bridge and any bridge
elements that interface with the South Island to the south end of the
south abutments at Willoughby Spit. This segment is located in
Construction Area 2 as shown in Figure 1.
Moorings at Willoughby Bay--Temporary moorings will be installed in
Willoughby Bay to support the construction of temporary work trestles
and permanent trestle bridges, and to provide a safe haven (harbor of
safe refuge) for vessels in the event of severe weather. Moorings will
consist of six dolphins--each consisting of three 24-inch steel piles--
and 50 42-inch steel pipe piles. The mooring dolphin piles and the
single mooring point piles will be installed under the existing IHA (85
FR 48153; August 10, 2020).
An additional 40 42-inch steel pipe piles will be installed in
Willoughby Bay to complete the safe haven (50 42-inch piles will be
installed under the existing IHA; HRCP 2020). The moorings will be
configured as two 2,000-feet long lines with a 42-inch mooring pile
every 80-feet. The piles will be installed using a vibratory hammer and
removed at the conclusion of the project using a vibratory hammer.
Temporary Work Trestles for Bridge Construction at Willoughby Bay--
The existing Willoughby Bay Bridge structure will be modified by
widening the two existing structures to the outside in both directions
to accommodate new travel lanes, shoulders, and new sound walls. This
will require installation of two to three additional piles at each pier
location on the outside of both eastbound and westbound structures. Two
temporary work trestles, each approximately 500 feet long and 45 feet
wide, will be installed along the outside edge of the existing
eastbound structure to provide access in the shallow water area near
both shorelines. Approximately 212 36-inch steel pipe piles will be
installed using a combination of vibratory and impact hammers to
support the temporary work trestles. The temporary steel piles will be
removed using a vibratory hammer.
Jump Trestle for Bridge Construction at Willoughby Bay--A
combination of jump trestles and working from the existing trestles
will be used to construct the widening of the existing Willoughby Bay
westbound roadway. Similar to other locations (e.g., Jump Trestle at
the North Trestle see Section), the jump trestle will be supported by
temporary 36-inch steel pipe pile foundations that will be installed,
removed, and reinstalled as the spans move forward using a combination
of vibratory and impact hammers for installation and vibratory hammers
for removal. Approximately 544 individual pile installations and 544
removals will be needed to support the jump trestle movement across
Willoughby Bay.
Templates and Permanent Piles at Willoughby Bay--Temporary template
piles (Table 7) will be used to guide installation of the permanent
concrete piles used to support widening of the eastbound and westbound
Willoughby Bay roadway. The templates will be supported by four
temporary steel piles up to 36-inch in diameter with one at each corner
of the template.
A vibratory hammer will be used to install and remove the temporary
36-inch steel piles supporting the template. Some areas near the
shorelines may require the use of a DTH hammer to install the templates
(Table 7).
Five hundred and four (504) 24-inch concrete square permanent piles
will be installed using an impact hammer and will remain in place at
the end of construction. Where geotechnical conditions require, the
permanent piles may also be installed via jetting. Where jetting is
required, an outer steel pipe pile casing (up to 42-inch in diameter)
may be installed using a vibratory hammer before installation of the
concrete pile. Approximately 300 casings (60 percent of the 504
concrete piles) will be installed prior to installing the concrete
piles. The casing will be driven and the sediment and sand removed from
the casing prior to installing the permanent pile. The casing will be
removed using a vibratory hammer.
Segment 3b--Willoughby Spit Laydown Area
This segment includes the Willoughby Spit Laydown Area which is a
temporary construction staging and laydown area that will include the
installation and removal of temporary piers. This segment is located in
Construction Area 4 as shown in Figure 1.
Temporary Docks on Spuds and Piles at the Willoughby Spit Laydown
Area--HRCP has been granted use of property on Willoughby Spit next to
the South Trestle-Bridge to be used for laydown areas and as a base for
marine operations. Two temporary piers will be constructed to allow
barge access: One will be a fixed pier on 44 36-inch steel pipe piles,
and the other will be a floating dock on 8 36-inch steel pipe (spuds)
piles. Piles will be installed using vibratory and impact hammers, as
well as a pile template. The pile template will be supported by four
temporary steel piles up to 36-inch in diameter (Table 7). The
temporary piers, including the steel pile foundations, will be removed
upon completion of the Project via vibratory hammer.
Temporary Finger Piers on Timber Piles at the Willoughby Spit
Laydown Area--The existing bulkheads and piers located on the inside of
Willoughby Spit will be repaired to provide access for crew boats and
similar-sized vessels. Three timber piers will replace the existing
piers and will be constructed using 36 16-inch CCA timber piles, each
pier consisting of 12 16-inch CCA timber piles. The piles will be
installed using a vibratory hammer. Any existing timber piers will be
pulled out of place.
HRCP plans to employ five methods of pile installation including
vibratory hammer, impact hammer, pre-drilling, jetting, and use of DTH
hammers. More than one installation method could be used within a day
and at each location and multiple piles could be installed and/or
removed concurrently. Steel pipe piles will most likely be installed
using a combination of vibratory (ICE 416L or similar) and impact
hammers (S35 or similar). Approximately 80 percent of the time steel
pipe piles will be installed using a vibratory hammer while an impact
hammer will be used approximately 20 percent of the time. Most piles
will be advanced using vibratory methods and then impact driven to
final tip elevation.
Temporary steel pile templates will be used to set permanent piles.
Templates will be positioned and held in place using spuds or steel
pipe piles, up to 36-inch diameter with one at each corner of the
template. Template piles are temporary and generally do not bear
significant vertical loads, therefore installation (i.e., driving) and
removal of template piles requires minimal driving time, estimated at
approximately 5 minutes per spud (see Table 7). Permanent concrete
piles will be installed using an impact hammer only, although permanent
concrete piles may also be installed via jetting at Willoughby Bay.
During jetting, high-pressure water is sprayed out of the bottom of the
pile to help penetrate dense sand layers and allow pile driving with
lower hammer impact energies. Jetting will only be conducted at depth
once sufficient resistance to pile installation has been met. Where
jetting is required, an outer steel pipe pile casing may be installed
before
[[Page 1596]]
installation of the square concrete piles at Willoughby Bay. Casings
will be driven using a vibratory hammer and the sediment and sand
removed from the casing prior to driving the permanent concrete pile.
HRCP assumed, and NMFS agrees, that jetting will be quieter than
vibratory installation of the same pile size, but data for this
activity are limited; therefore, sound source levels (SSLs) for
vibratory installation were applied to jetting.
Pre-drilling will be performed on the 54-inch concrete cylinder
permanent piles without the use of a casing in the open. The drill,
drill steel, and auger will be in leads and either attached to the pile
leads or used independently and indexed to the template to resist
rotation. A 54-inch diameter auger 10-feet or less in height is
expected to be employed. Pre-drilling will be conducted to loosen soils
directly underneath the pile to maximize pile advancement before the
drive and shorten the length of driving time. Pre-drilling may reduce
driving times by as much as 50 percent and pre-drilling depth is
expected to be less than half the pile length. HRCP may drill to within
3-4 diameters above the final tip elevation in cases of dense sand.
HRCP assumed and NMFS agrees that use of the drill, drill turntable,
drill steel, drill auger, and drill bit will not result in harassment.
These devices have low source levels and, therefore, low signal-to-
noise ratios. The signal characteristics (continuous noise) would be
occurring in a relatively noisy coastal environment where low-level
continuous noise is common. Therefore, they would be unlikely to
provoke a reaction consistent with what we would consider to be
harassment. Therefore, harassment zone sizes were not estimated for
these activities. These devices simply rotate in the sediments and do
not displace them without creating a hole. No pile is installed during
pre-drilling, and much less energy is expended than during pile
installation. The equipment and nature of the act of pre-drilling in
soils produce minimal noise and the pre-drilling will significantly
reduce the driving time which in turn reduces the total noise levels.
The pile installation methods used will depend on sediment depth
and conditions at each pile location. Table 2 through Table 7 provides
additional information on the pile driving operation including
estimated pile driving times. Note that the sum of the days of pile
installation and removal is greater than the anticipated number of days
because more than one pile installation method will be used within a
day and at each location. The overall number of anticipated days of
pile installation and removal is 312 per year, based on a six-day work
week for years 1-4. Year 5 will require an estimated 181 days of in-
water work. It is possible that installation and removal numbers might
shift from one month to another depending on schedule constraints.
HRCP will employ a bubble curtain when installing steel pipe piles
in water depths greater than 20 feet to minimize hydroacoustic impacts
caused by the impact hammer. Bubble curtains will be used at the South
Island to install a portion of the permanent settlement reduction piles
and deep foundation piles and at the South Trestle to install a portion
of the Temporary MOT Trestle, Jump Trestle, and Work Trestle.
Before installing steel pipe piles near shorelines protected with
rock armor and/or rip rap (e.g., South Island shoreline; North Shore
shoreline) the rock armoring that protects the shoreline will need to
be temporarily shifted to an adjacent area to allow for the
installation of the piles. The rock armor should only be encountered at
the shoreline and at relatively shallow depths below the mudline. Any
rock armor stone and/or rip rap that has been moved will be reinstalled
near its original location following the completion of pile
installation.
DTH pile installation uses both rotary and percussion-type drill
devices and will be used frequently. The device consists of a drill bit
that drills through stone using both rotary and pulse impact
mechanisms. This breaks up the stone to allow removal of the fragments
and insertion of the pile. The pile is usually advanced at the same
time that drilling occurs. Drill cuttings are expelled from the top of
the pile using compressed air and will be directed through a pipe to a
designated location for waste.
Piles may be also be installed without moving the armor stone by
first drilling through the stone with a DTH hammer. It is estimated
that drilling with a DTH hammer will be used for approximately 1 to 2
hours per pile, when necessary. It is anticipated that approximately 7
percent of the North Shore Work Trestle piles, 4 percent of the North
Trestle Jump Trestle piles, 7 percent of the North Trestle Demolition
Trestle piles, 100 percent of the North Trestle Casings, 14 percent of
the South Trestle Work Trestle piles, 6 percent of the South Trestle
Jump Trestle piles, 10 percent of the South Trestle Temporary MOT
Trestle piles, 17 percent of the South Trestle Demolition Trestle
piles, 100 percent of the South Trestle Casings, and 10 percent of the
South Island deep foundation piles may require installation with a DTH
hammer (See Table 2 through Table 6).
Temporary steel sheet piles and steel pipe piles will be removed
using a vibratory hammer or cut to approximately 3 feet below the
mudline. Temporary concrete piles will only be removed by cutting to
approximately 3 feet below the mudline.
Table 2 through 6 below show the number and types of piles planned
for installation and removal each year by component and segment while
Table 7 shows the total number of template piles over five years by
location.
Table 2--Numbers and Types of Piles To Be Installed and Removed During LOA Year One for Each HRBT Project Component and Segment
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Average
Total down-the- Number of Average Approximate Number of Estimated Number of
Pile size/ type number of Total number Embedment Number of hole piles vibratory number of piles per total number days of
Project component and material piles to of piles to length piles down- duration vibrated/ duration impact day per of hours of installation
be be removed (feet) the- hole per pile hammered per pile strikes per hammer installation and removal
installed (minutes) (minutes) pile and removal
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
North Trestle (Segment 1b)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Permanent Piles............... 54-inch Concrete 188 0 140 .......... .......... 188 .......... 2,100 1 376 188
Cylinder Pipe.
Casing........................ 60-inch Steel 15 0 60 15 120 .......... .......... ............ 3 30 5
Pipe.
North Shore Abutment.......... AZ 700-19 Steel 63 63 20 .......... .......... 126 30 ............ 10 63 13
Sheet.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 1597]]
North Island (Segment 2a)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Hampton Creek Approach Channel Existing, 36-inch 1 1 ........... .......... .......... 1 50 ............ 1 2 1
Marker. Steel Pipe.
North Island Expansion........ AZ 700-26 Steel 176 176 40 .......... .......... 352 30 ............ 10 176 35
Sheet.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Willoughby Bay (Segment 3c)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Work Trestle.................. 36-inch Steel 212 0 100 .......... .......... 212 50 40 2 177 106
Pipe.
Moorings (Safe Haven)......... 42-inch Steel 40 0 60 .......... .......... 40 30 ............ 6 20 7
Pipe.
Permanent Piles............... 24-inch Concrete 402 0 140 .......... .......... 402 .......... 2,100 1 804 402
Square Pipe.
Casing........................ 42-inch Steel 240 240 60 .......... .......... 480 30 ............ 6 160 80
Pipe.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Willoughby Spit (Segment 3b)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Dock on Spuds, Floating Dock.. 36-inch Steel 8 0 100 .......... .......... 8 50 40 3 7 3
Pipe.
Dock on Piles, Fixed Pier..... 36-inch Steel 44 0 100 .......... .......... 44 50 40 3 37 15
Pipe.
Finger Piers on Timber Piles.. 16-inch CCA* 36 0 60 .......... .......... 36 30 ............ 4 18 9
Timber.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
South Trestle (Segment 3a)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Work Trestle.................. 36-inch Steel 156 0 100 22 120 134 50 40 2 130 78
Pipe.
Temporary MOT * Trestle....... 36-inch Steel 113 0 100 11 120 102 50 40 2 85 51
Pipe.
Casing........................ 42-inch Steel 30 0 60 .......... .......... 30 30 ............ 6 15 5
Pipe.
Permanent Piles............... 54-inch Concrete 252 0 140 .......... .......... 252 .......... 2,100 1 504 252
Cylinder Pipe.
Casing........................ 60-inch Steel 65 0 60 65 120 .......... .......... ............ 3 130 22
Pipe.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
South Island (Segment 2a)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Settlement Reduction Piles.... 24-inch Steel 24 0 85 .......... .......... 24 60 40 6 24 4
Pipe.
Deep Foundation Piles......... 30-inch Steel 82 0 85 8 120 74 60 40 6 82 14
Pipe, Concrete
Filled.
Moorings...................... 42-inch Steel 25 0 60 .......... .......... 25 30 ............ 6 13 4
Pipe.
South Island Abutment......... AZ 700-19 Steel 12 0 20 .......... .......... 12 30 ............ 10 6 2
Sheet.
----------------------------------------------------------------------------------------------------------------------------------------------
Total..................... ................. 2,184 480 ........... .......... .......... .......... .......... ............ .......... .............. 1,296
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Table 3--Numbers and Types of Piles To Be Installed and Removed During LOA Year Two for Each HRBT Project Component and Segment
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Average
Total down-the- Number of Average Approximate Number of Estimated Number of
Pile size/ type number of Total number Embedment Number of hole piles vibratory number of piles per total number days of
Project component and material piles to of piles to length piles down- duration vibrated/ duration impact day per of hours of installation
be be removed (feet) the- hole per pile hammered per pile strikes per hammer installation and removal
installed (minutes) (minutes) pile and removal
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
North Trestle (Segment 1b)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
North Shore Work Trestle...... 36-inch Steel 0 194 100 .......... .......... 194 50 40 3 162 65
Pipe.
Work Trestle.................. 36-inch Steel 182 ............ 100 12 120 170 50 40 2 152 91
Pipe.
Jump Trestle.................. 36-inch Steel 42 38 100 3 120 77 50 40 2 65 39
Pipe.
[[Page 1598]]
Permanent Piles............... 54-inch, Concrete 102 0 140 .......... .......... 102 .......... 2,100 1 204 102
Cylinder Pipe.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
North Island (Segment 2a)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
North Island Abutment......... AZ 700-19 Steel 96 0 20 .......... .......... 96 30 ............ 10 48 10
Sheet.
Willoughby Bay (Segment 3c)...
Jump Trestle.................. 36-inch Steel 84 76 100 .......... .......... 160 50 40 2 134 80
Pipe.
Work Trestle.................. 36-inch Steel 0 126 100 .......... .......... 126 50 ............ 2 105 63
Pipe.
Permanent Piles............... 24-inch Concrete 102 0 140 .......... .......... 102 .......... 2,100 1 204 102
Square Pipe.
Casing........................ 42-inch Steel 60 60 60 .......... .......... 120 30 ............ 6 60 20
Pipe.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
South Trestle (Segment 3a)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Work Trestle.................. 36-inch Steel 100 0 100 14 120 86 50 40 2 84 50
Pipe.
Jump Trestle.................. 36-inch Steel 175 175 100 10 120 350 50 40 2 292 175
Pipe.
Temporary MOT * Trestle....... 36-inch Steel 105 0 100 10 120 95 50 ............ 2 80 48
Pipe.
Permanent Piles............... 54-inch Concrete 168 0 140 .......... .......... 168 .......... 2,100 1 336 168
Cylinder Pipe.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
South Island (Segment 2a)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Settlement Reduction Piles.... 24-inch Steel 370 0 85 .......... .......... 370 60 40 6 370 62
Pipe, Steel.
Deep Foundation Piles......... 30-inch Steel 425 0 85 42 120 383 60 40 6 425 71
Pipe, Concrete
Filled.
South Island Abutment......... AZ 700-19 Steel 12 24 20 .......... .......... 36 30 ............ 10 18 4
Sheet.
South Island Expansion........ AZ 700-26 Steel 378 378 70 .......... .......... 756 30 ............ 10 189 76
Sheet.
----------------------------------------------------------------------------------------------------------------------------------------------
Total..................... ................. 2,401 1,071 ........... .......... .......... .......... .......... ............ .......... .............. 1,226
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Table 4--Numbers and Types of Piles To Be Installed and Removed During LOA Year Three for Each HRBT Project Component and Segment
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Average
Total down- the- Number of Average Approximate Number of Estimated Number of
Pile size/type number of Total number Embedment Number of hole piles vibratory number of piles per total number days of
Project component and material piles to of piles to length piles down- duration vibrated/ duration impact day per of hours of installation
be be removed (feet) the-hole per pile hammered per pile strikes per hammer installation and removal
installed (minutes) (minutes) pile and removal
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
North Trestle (Segment 1b)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Jump Trestle.................. 36-inch Steel 228 232 100 9 120 451 50 40 2 376 226
Pipe.
Permanent Piles............... 54-inch, Concrete 187 0 140 .......... .......... 187 .......... 2,100 1 374 187
Cylinder Pipe.
North Shore Abutment.......... AZ 700-19 Steel 62 62 20 .......... .......... 124 30 ............ 10 62 13
Sheet.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
North Island (Segment 2a)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
North Island Abutment......... AZ 700-19 Steel 32 128 20 .......... .......... 160 30 ............ 10 80 16
Sheet.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Willoughby Bay (Segment 3c)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Jump Trestle.................. 36-inch Steel 460 468 100 .......... .......... 928 50 40 2 774 464
Pipe.
Work Trestle.................. 36-inch Steel 0 86 100 .......... .......... 86 50 ............ 2 72 43
Pipe.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
South Trestle (Segment 3a)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Jump Trestle.................. 36-inch Steel 245 245 100 14 120 476 50 40 2 397 238
Pipe.
[[Page 1599]]
Demolition Trestle............ 36-inch Steel 15 0 100 2 120 13 50 40 2 13 30
Pipe.
Work Trestle.................. 36-inch Steel 0 182 100 .......... .......... 182 50 ............ 2 152 91
Pipe.
Temporary MOT * Trestle....... 36-inch Steel 0 110 100 .......... .......... 110 50 ............ 2 92 55
Pipe.
Permanent Piles............... 54-inch Concrete 196 0 140 .......... .......... 196 .......... 2,100 1 392 196
Cylinder Pipe.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
South Island (Segment 2a)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
South Island Abutment......... AZ 700-19 Steel 46 46 20 .......... .......... 92 30 ............ 10 46 10
Sheet.
----------------------------------------------------------------------------------------------------------------------------------------------
Total..................... ................. 1,471 1,559 ........... .......... .......... .......... .......... ............ .......... .............. 1,569
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Table 5--Numbers and Types of Piles To Be Installed and Removed During LOA Year Three for Each HRBT Project Component and Segment
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Average
Total down- the- Number of Average Approximate Number of Estimated Number of
Pile size/type number of Total number Embedment Number of hole piles vibratory number of piles per total number days of
Project component and material piles to of piles to length piles down- duration vibrated/ duration impact day per of hours of installation
be be removed (feet) the-hole per pile hammered per pile strikes per hammer installation and removal
installed (minutes) (minutes) pile and removal
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
North Trestle (Segment 1b)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Demolition Trestle............ 36-inch Steel 344 172 100 24 120 492 50 40 2 410 246
Pipe.
Permanent Piles............... 54-inch, Concrete 85 0 140 .......... .......... 85 .......... 2,100 1 170 85
Cylinder Pipe.
North Shore Abutment.......... AZ 700-19 Steel 62 62 20 .......... .......... 124 30 ............ 10 62 13
Sheet.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
South Trestle (Segment 3a)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Demolition Trestle............ 36-inch Steel 57 72 100 10 120 119 50 40 2 99 60
Pipe.
Work Trestle.................. 36-inch Steel 0 74 100 .......... .......... 74 50 ............ 2 62 37
Pipe.
Temporary MOT * Trestle....... 36-inch Steel 0 108 100 .......... .......... 108 50 ............ 2 90 54
Pipe.
Permanent Piles............... 54-inch Concrete 194 0 140 .......... .......... 194 .......... 2,100 1 388 194
Cylinder Pipe.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
South Island (Segment 2a)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TBM Platform.................. 36-inch Steel 0 216 140 .......... .......... 216 60 ............ 2 216 108
Pipe.
Conveyor Trestle.............. 36-inch Steel 0 84 100 .......... .......... 84 50 ............ 3 70 42
Pipe.
----------------------------------------------------------------------------------------------------------------------------------------------
Total..................... ................. 742 788 ........... .......... .......... .......... .......... ............ .......... .............. 839
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Table 6--Numbers and Types of Piles to be Installed and Removed during LOA Year Five for Each HRBT Project Component and Segment
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Average
Total down- the- Number of Average Approximate Number of Estimated Number of
Pile size/type number of Total number Embedment Number of hole piles vibratory number of piles per total number days of
Project component and material piles to of piles to length piles down- duration vibrated/ duration impact day per of hours of installation
be be removed (feet) the-hole per pile hammered per pile strikes per hammer installation and removal
installed (minutes) (minutes) pile and removal
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
North Trestle (Segment 1b)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Moorings...................... 42-inch Steel 0 36 60 .......... .......... 36 30 ............ 6 18 6
Pipe.
Moorings...................... 24-inch Steel 0 30 60 .......... .......... 30 30 ............ 6 15 5
Pipe.
Work Trestle.................. 36-inch Steel 0 182 100 .......... .......... 182 50 ............ 2 152 91
Pipe.
Demolition Trestle............ 36-inch Steel 0 172 100 .......... .......... 172 50 ............ 2 144 86
Pipe.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 1600]]
North Island (Segment 2a)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Moorings...................... 42-inch Steel 0 80 60 .......... .......... 80 30 ............ 6 40 14
Pipe.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Willoughby Bay (Segment 3c)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Moorings...................... 42-inch Steel 0 50 60 .......... .......... 50 30 ............ 6 25 9
Pipe.
Moorings...................... 24-inch Steel 0 18 60 .......... .......... 18 30 ............ 6 9 3
Pipe.
Moorings...................... 42-inch Steel 0 90 60 .......... .......... 90 30 ............ 6 45 15
(Safe Haven).................. Pipe.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Willoughby Spit (Segment 3b)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Dock on Spuds, Floating Dock.. 36-inch Steel 0 8 100 .......... .......... 8 50 ............ 3 7 3
Pipe.
Dock on Piles, Fixed Pier..... 36-inch Steel 0 44 100 .......... .......... 44 50 ............ 3 37 15
Pipe.
Finger Piers on Timber Piles.. 16-inch CCA *, 0 36 60 .......... .......... 36 30 ............ 4 18 9
Timber.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
South Trestle (Segment 3a)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Moorings...................... 42-inch Steel 0 41 60 .......... .......... 41 30 ............ 6 21 7
Pipe.
Moorings...................... 24-inch Steel 0 18 60 .......... .......... 18 30 ............ 6 9 3
Pipe.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
South Island (Segment 2a)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Mooring....................... 42-inch Steel 0 25 60 .......... .......... 25 30 ............ 6 13 5
Pipe.
----------------------------------------------------------------------------------------------------------------------------------------------
Total..................... ................. 0 830 ........... .......... .......... .......... .......... ............ .......... .............. 271
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Table 7--Numbers of Template Piles (Up to 36-Inch Steel Pipe Piles) To Be Installed and Removed Using a Vibratory Hammer for the HRBT Project
--------------------------------------------------------------------------------------------------------------------------------------------------------
Average Number of piles
Estimated Estimated Average down- vibratory per day per
Project component/location Pile size/type and number of number of the-hole duration per component
material template piles template piles duration per template pile (install and
to be installed to be removed pile (minutes) (minutes) removal)
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Trestle Permanent Piles.......... 54-inch Concrete Cylinder 750 750 ............... 5 8
Pipe.
South Trestle Permanent Piles.......... 54-inch Concrete Cylinder 1080 1080 ............... 5 8
Pipe.
Willoughby Bay Permanent Piles......... 24-inch Concrete Square 672 672 ............... 5 8
Pipe.
Willoughby Spit Fixed Pier *........... 36-inch Steel Pipe....... 59 59 ............... 5 16
Willoughby Spit Floating Pier *........ 36-inch Steel Pipe....... 11 11 ............... 5 16
South Island Deep Foundation Piles..... 30-inch Steel Pipe, 676 676 120 5 16
Concrete Filled.
South Island Settlement Reduction Piles 24-inch Steel Pipe....... 526 526 ............... 5 16
-------------------------------------------------------------------------------------
Estimated Total Template Pile ......................... 3,774 3,774 ............... ............... ................
Driving Actions.
-------------------------------------------------------------------------------------
Total number of Temporary ......................... 7,584
Template Pile Driving action.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history, of the potentially affected species.
Additional information regarding population trends and threats may be
found in NMFS' Stock Assessment Reports (SAR); https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region and more general information about
these species (e.g., physical and behavioral descriptions) may be found
[[Page 1601]]
on NMFS' website (https://www.fisheries.noaa.gov/find-species).
Table 8 lists all species with expected potential for occurrence in
the project area and summarizes information related to the population
or stock, including regulatory status under the MMPA and ESA and
potential biological removal (PBR), where known. For taxonomy, we
follow Committee on Taxonomy (2020). PBR is defined by the MMPA as the
maximum number of animals, not including natural mortalities, that may
be removed from a marine mammal stock while allowing that stock to
reach or maintain its optimum sustainable population (as described in
NMFS' SARs). While no mortality is anticipated or authorized here, PBR
and annual serious injury and mortality from anthropogenic sources are
included here as gross indicators of the status of the species and
other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS's stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS's U.S. Atlantic and Gulf of Mexico SARs (e.g., Hayes et al.,
2020). All values presented in Table 8 are the most recent available at
the time of publication and are available in the 2019 SARs (Hayes et
al., 2020).
Table 8--Marine Mammal Species Likely To Occur Near the Project Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stock abundance (CV,
ESA/MMPA status; Nmin, most recent Annual M/
Common name Scientific name Stock strategic (Y/N) abundance survey) \2\ PBR SI \3\
\1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenopteridae (rorquals):
Humpback whale.................. Megaptera novaeangliae. Gulf of Maine.......... -,-; N 1,396 (0; 1,380; see 22 12.15
SAR).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
Bottlenose dolphin.............. Tursiops truncatus..... Western North Atlantic -,-; Y 6,639 (0.41; 4,759; 48 6.1-13.2
(WNA) Coastal, 2011).
Northern Migratory.
WNA Coastal, Southern -,-; Y 3,751 (0.06; 2,353; 23 0-14.3
Migratory. 2011).
Northern North Carolina -,-; Y 823 (0.06; 782; 2013). 7.8 0.8-18.2
Estuarine System
(NNCES).
Family Phocoenidae (porpoises):
Harbor porpoise................. Phocoena phocoena...... Gulf of Maine/Bay of -, -; N 95,543 (0.31; 74,034; 851 217
Fundy. see SAR).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulina......... WNA.................... -; N 75,834 (0.15; 66,884, 2,006 350
see SAR).
Gray seal \4\................... Halichoerus grypus..... WNA.................... -; N 27,131 (0.19, 23,158, 1,359 5,410
see SAR).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR 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\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
\4\ The NMFS stock abundance estimate applies to U.S. population only, however the actual stock abundance is approximately 451,431.
As indicated above, all five species (with seven managed stocks) in
Table 8 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur, and we have proposed
authorizing take. While North Atlantic right whales (Eubalaena
glacialis), minke whales (Balaenoptera acutorostrata acutorostrata),
and fin whales (Balaenoptera physalus) have been documented in the
area, the temporal and/or spatial occurrence of these whales is such
that take is not expected to occur, and they are not discussed further
beyond the explanation provided here.
Based on sighting data and passive acoustic studies, the North
Atlantic right whale could occur off Virginia year-round (DoN 2009;
Salisbury et al., 2016). They have also been reported seasonally off
Virginia during migrations in the spring, fall, and winter (CeTAP 1981,
1982; Niemeyer et al., 2008; McLellan 2011b, 2013; Mallette et al.,
2016a, 2016b, 2017, 2018a; Palka et al., 2017; Cotter 2019). Right
whales are known to frequent the coastal waters of the mouth of the
Chesapeake Bay (Knowlton et al., 2002) and the area is a seasonal
management area (November 1-April 30) mandating reduced ship speeds out
to approximately 20 nautical miles for the species; however, the
project area is further inside the Bay.
North Atlantic right whales have stranded in Virginia, one each in
2001, 2002, 2004, 2005: Three during winter (February and March) and
one in summer (September) (Costidis et al., 2017, 2019). In January
2018, a dead, entangled North Atlantic right whale
[[Page 1602]]
was observed floating over 60 miles offshore of Virginia Beach
(Costidis et al., 2019). All North Atlantic right whale strandings in
Virginia waters have occurred on ocean-facing beaches along Virginia
Beach and the barrier islands seaward of the lower Delmarva Peninsula
(Costidis et al., 2017). Due to the low occurrence of North Atlantic
right whales near the project area, NMFS is not proposing to authorize
take of this species.
Fin whales have been sighted off Virginia (Cetacean and Turtle
Assessment Program (CeTAP) 1981, 1982; Swingle et al., 1993; DoN 2009;
Hyrenbach et al., 2012; Barco 2013; Mallette et al., 2016a, b;
Aschettino et al., 2018; Engelhaupt et al., 2017, 2018; Cotter 2019),
and in the Chesapeake Bay (CeTAP 1981, 1982; Morgan et al., 2002; Barco
2013; Aschettino et al., 2018); however, they are not likely to occur
in the project area. Sightings have been documented around the
Chesapeake Bay Bridge Tunnel (CBBT), which is approximately 17 km from
the project site, during the winter months (CeTAP 1981, 1982; Barco
2013; Aschettino et al., 2018).
Eleven fin whale strandings have occurred off Virginia from 1988 to
2016 mostly during the winter months of February and March, followed by
a few in the spring and summer months (Costidis et al., 2017). Six of
the strandings occurred in the Chesapeake Bay (three on eastern shore;
three on western shore) with the remaining five occurring on the
Atlantic coast (Costidis et al., 2017. Documented strandings near the
project area have occurred: February 2012, a dead fin whale washed
ashore on Oceanview Beach in Norfolk (Swingle et al., 2013); December
2017, a live fin whale stranded on a shoal in Newport News and died at
the site (Swingle et al., 2018); February 2014, a dead fin whale
stranded on a sand bar in Pocomoke Sound near Great Fox Island,
Accomack (Swingle et al., 2015); and, March 2007, a dead fin whale near
Craney Island, in the Elizabeth River, in Norfolk (Barco 2013). Only
stranded fin whales have been documented in the project area; no free-
swimming fin whales have been observed. Due to the low occurrence of
fin whales in the project area, NMFS is not proposing to authorize take
of this species.
Minke whales have been sighted off Virginia (CeTAP 1981, 1982;
Hyrenbach et al. 2012; Barco 2013; Mallette et al., 2016a, b; McLellan
2017; Engelhaupt et al., 2017, 2018; Cotter 2019), near the CBBT
(Aschettino et al., 2018), but sightings in the project area are from
strandings (Jensen and Silber 2004; Barco 2013; DoN 2009). In August
1994, a ship strike incident involved a minke whale in Hampton Roads
(Jensen and Silber 2004; Barco 2013). It was reported that the animal
was struck offshore and was carried inshore on the bow of a ship (DoN
2009). Twelve strandings of minke whales have occurred in Virginia
waters from 1988 to 2016 (Costidis et al., 2017). There have been six
minke whale stranding from 2017 through 2020 in Virginia waters.
Because all known minke whale occurrences in the project area are due
to strandings, NMFS is not proposing to authorize take of this species.
Humpback Whale
Humpback whales are distributed worldwide in all major oceans and
most seas. Most humpback whale sightings are in nearshore and
continental shelf waters; however, humpback whales frequently travel
through deep oceanic waters during migration (Calambokidis et al.,
2001; Clapham, P.J. and Mattila, D.K., 1990). Prior to 2016, humpback
whales were listed under the ESA as an endangered species worldwide.
Following a 2015 global status review (Bettridge et al., 2015), NMFS
established 14 DPSs with different listing statuses (81 FR 62259;
September 8, 2016) pursuant to the ESA. Humpback whales in the project
area are expected to be from the West Indies DPS, which consists of the
whales whose breeding range includes the Atlantic margin of the
Antilles from Cuba to northern Venezuela, and whose feeding range
primarily includes the Gulf of Maine, eastern Canada, and western
Greenland. The West Indies DPS was delisted in 2016. Bettridge et al.
(2003) estimated the size of the West Indies DPS at 12,312 (95 percent
CI 8,688-15,954) whales in 2004-05, which is consistent with previous
population estimates of approximately 10,000-11,000 whales (Stevick et
al., 2003; Smith et al., 1999) and the increasing trend for the West
Indies DPS (Bettridge et al., 2015).
Although humpback whales are migratory between feeding areas and
calving areas, individual variability in the timing of migrations may
result in the presence of individuals in high-latitude areas throughout
the year (Straley, 1990). Records of humpback whales off the U.S. mid-
Atlantic coast (New Jersey to North Carolina) from January through
March suggest these waters may represent a supplemental winter feeding
ground used by juvenile and mature humpback whales of U.S. and Canadian
North Atlantic stocks (LaBrecque et al., 2015).
The immediate project area is not within normal humpback whale
feeding or migration areas. They are most likely to occur near the
mouth of the Chesapeake Bay and coastal waters of Virginia Beach
between January and March; however, they could be found in the area
year-round, based on shipboard sighting and stranding data (Barco and
Swingle, 2014; Aschettino et al., 2015; 2016; 2017; 2018). Photo-
identification data support the repeated use of the mid-Atlantic region
by individual humpback whales. Results of the vessel surveys show site
fidelity in the survey area for some individuals and a high level of
occurrence within shipping channels (Aschettino et al., 2015; 2016;
2017; 2018). Nearshore surveys conducted in early 2015 reported 61
individual humpback whale sightings, and 135 individual humpback whale
sightings in late 2015 through May 2016 (Aschettino et al., 2016).
Subsequent surveys confirmed the occurrence of humpback whales in the
nearshore survey area: 248 individuals were detected in 2016-2017
surveys (Aschettino et al., 2017), 32 individuals were detected in
2017-2018 surveys (Aschettino et al., 2018), and 80 individuals were
detected in 2019 surveys (Aschettino et al., 2019). Sightings in the
Hampton Roads area in the vicinity of Naval Station (NAVSTA) Norfolk
were reported in nearshore surveys and through tracking of satellite-
tagged whales in 2016, 2017 and 2019. The numbers of whales detected,
most of which were juveniles, reflect the varying level of survey
effort and changes in survey objectives from year to year, and do not
indicate abundance trends over time. Therefore, humpback whales could
occur near the Project area and incidental take could result from
exposure to underwater sounds during pile driving and removal.
Bottlenose Dolphin
Along the U.S. East Coast and northern Gulf of Mexico, there are
currently 53 management stocks identified by NMFS in the western North
Atlantic and Gulf of Mexico, including oceanic, coastal, and estuarine
stocks (Hayes et al., 2020; Waring et al., 2016).
The population structure of bottlenose dolphins off Virginia is
complex. There are two morphologically and genetically distinct
bottlenose dolphin morphotypes (distinguished by physical differences)
described as coastal and offshore forms (Duffield et al., 1983;
Duffield, 1986). The offshore form is larger in total length and skull
length, and has wider nasal bones than the coastal form. Both inhabit
waters in the western North Atlantic Ocean and Gulf of Mexico (Curry
and Smith, 1997;
[[Page 1603]]
Mead and Potter, 1995) along the U.S. Atlantic coast. The coastal
morphotype of bottlenose dolphin is continuously distributed along the
Atlantic coast south of Long Island, New York, around the Florida
peninsula, and along the Gulf of Mexico coast. This type typically
occurs in waters less than 20 meters deep (Waring et al., 2015). The
range of the offshore bottlenose dolphin includes waters beyond the
continental slope (Kenney R. D., 1990), and offshore bottlenose
dolphins may move between the Gulf of Mexico and the Atlantic (Wells et
al., 1999). Bottlenose dolphins are the most abundant marine mammal
along the Virginia coast and within the Chesapeake Bay, typically
traveling in groups of 2 to 15 individuals, but occasionally in groups
of over 100 individuals (Engelhaupt et al., 2014; 2015; 2016).
Two coastal stocks are likely to be present in the HRBT project
area: Western North Atlantic Northern Migratory Coastal stock and
Western North Atlantic Southern Migratory Coastal stock. Additionally,
the Northern North Carolina Estuarine System stock may occur in the
project area.
The northern migratory coastal stock is best defined by its
distribution during warm water months when the stock occupies coastal
waters from the shoreline to approximately the 20-m isobath between
Assateague, Virginia, and Long Island, New York (Garrison et al. 2017).
The stock migrates in late summer and fall and, during cold water
months (best described by January and February), occupies coastal
waters from approximately Cape Lookout, North Carolina, to the North
Carolina/Virginia border (Garrison et al. 2017b). Historically, common
bottlenose dolphins have been rarely observed during cold water months
in coastal waters north of the North Carolina/Virginia border, and
their northern distribution in winter appears to be limited by water
temperatures. Overlap with the southern migratory coastal stock in
coastal waters of northern North Carolina and Virginia is possible
during spring and fall migratory periods, but the degree of overlap is
unknown and it may vary depending on annual water temperature (Garrison
et al. 2016). When the stock has migrated in cold water months to
coastal waters from just north of Cape Hatteras, North Carolina, to
just south of Cape Lookout, North Carolina, it overlaps spatially with
the Northern North Carolina Estuarine System (NNCES) Stock (Garrison et
al. 2017b).
The southern migratory coastal stock migrates seasonally along the
coast between North Carolina and northern Florida (Garrison et al.
2017b). During January-March, the southern migratory coastal stock
appears to move as far south as northern Florida. During April-June,
the stock moves back north past Cape Hatteras, North Carolina (Garrison
et al. 2017b), where it overlaps, in coastal waters, with the NNCES
stock (in waters <=1 km from shore). During the warm water months of
July-August, the stock is presumed to occupy coastal waters north of
Cape Lookout, North Carolina, to Assateague, Virginia, including the
Chesapeake Bay.
The NNCES stock is best defined as animals that occupy primarily
waters of the Pamlico Sound estuarine system (which also includes Core,
Roanoke, and Albemarle sounds, and the Neuse River) during warm water
months (July-August). Members of this stock also use coastal waters
(<=1 km from shore) of North Carolina from Beaufort north to Virginia
Beach, Virginia, including the lower Chesapeake Bay. A community of
NNCES dolphins are likely year-round Bay residents (Patterson, Pers.
Comm).
Vessel surveys conducted along coastal and offshore transects from
NAVSTA Norfolk to Virginia Beach in most months from August 2012 to
August 2015 reported bottlenose dolphins throughout the survey area,
including the vicinity of NAVSTA Norfolk (Engelhaupt et al., 2014;
2015; 2016). The final results from this project confirmed earlier
findings that bottlenose dolphins are common in the study area, with
highest densities in the coastal waters in summer and fall months.
However, bottlenose dolphins do not completely leave this area during
colder months, with approximately 200-300 individuals still present in
winter and spring months (Engelhaupt et al., 2016).
Harbor Porpoise
Harbor porpoises inhabit cool temperate-to-subpolar waters, often
where prey aggregations are concentrated (Watts and Gaskin, 1985).
Thus, they are frequently found in shallow waters, most often near
shore, but they sometimes move into deeper offshore waters. Harbor
porpoises are rarely found in waters warmer than 63 degrees Fahrenheit
(17 degrees Celsius) (Read 1999) and closely follow the movements of
their primary prey, Atlantic herring (Gaskin 1992).
In the western North Atlantic, harbor porpoise range from
Cumberland Sound on the east coast of Baffin Island, southeast along
the eastern coast of Labrador to Newfoundland and the Gulf of St.
Lawrence, then southwest to about 34 degrees North on the coast of
North Carolina (Waring et al., 2016). During winter (January to March),
intermediate densities of harbor porpoises can be found in waters off
New Jersey to North Carolina, and lower densities are found in waters
off New York to New Brunswick, Canada (Waring et al., 2016). Harbor
porpoises sighted off the mid-Atlantic during winter include porpoises
from other western North Atlantic populations (Rosel et al., 1999).
There does not appear to be a temporally coordinated migration or a
specific migratory route to and from the Bay of Fundy region (Waring et
al., 2016). During fall (October to December) and spring (April to
June), harbor porpoises are widely dispersed from New Jersey to Maine,
with lower densities farther north and south (LaBrecque et al., 2015).
Based on stranding reports, passive acoustic recorders, and
shipboard surveys, harbor porpoise occur in coastal waters primarily in
winter and spring months, but there is little information on their
presence in the Chesapeake Bay. They do not appear to be abundant in
the HRBT project area in most years, but this is confounded by wide
variations in stranding occurrences over the past decade. Since 1999,
stranding incidents have ranged widely from a high of 40 in 1999 to 2
in 2011, 2012, and 2016 (Barco et al. 2017).
Harbor Seal
The Western North Atlantic stock of harbor seals occurs in the HRBT
project area. Harbor seal distribution along the U.S. Atlantic coast
has shifted in recent years, with an increased number of seals reported
from southern New England to the mid-Atlantic region (DiGiovanni et
al., 2011; Hayes et al., 2017; Kenney R. D. 2019; Waring et al., 2016).
Harbor seals are the most common seal in Virginia (Barco and Swingle
2014) and regular sightings of seals in Virginia have become a common
occurrence in winter and early spring (Costidis et al., 2019). Winter
haulout sites for harbor seals have been documented in the Chesapeake
Bay at the CBBT, on the Virginia Eastern Shore, and near Oregon Inlet,
North Carolina (Waring et al., 2016; Rees et al., 2016; Jones et al.,
2018).
Harbor seals regularly haul out on rocks around the portal islands
of the CBBT and on mud flats on the nearby southern tip of the Eastern
Shore from December through April (Rees et al., 2016; Jones et al.,
2018). Seals captured in 2018 on the Eastern Shore and tagged with
satellite-tracked tags that lasted from 2 to 5 months spent at least 60
days in Virginia waters before departing
[[Page 1604]]
the area. All tagged seals returned regularly to the capture site while
in Virginia waters, but individuals utilized offshore and Chesapeake
Bay waters to different extents (Ampela et al., 2019). The area that
was utilized most heavily was near the Eastern Shore capture site, but
some seals ranged into the Chesapeake Bay.
Gray Seal
The Western North Atlantic stock of gray seal occurs in the project
area. The western North Atlantic stock is centered in Canadian waters,
including the Gulf of St. Lawrence and the Atlantic coasts of Nova
Scotia, Newfoundland, and Labrador, Canada, and the northeast U.S.
continental shelf (Hayes et al., 2017). Gray seals range south into the
northeastern United States, with strandings and sightings as far south
as North Carolina (Hammill et al., 1998; Waring et al., 2004). Gray
seal distribution along the U.S. Atlantic coast has shifted in recent
years, with an increased number of seals reported in southern New
England (DiGiovanni et al., 2011; Kenney R.D., 2019; Waring et al.,
2016). Recent sightings included a gray seal in the lower Chesapeake
Bay during the winter of 2014 to 2015 (Rees et al., 2016). Along the
coast of the United States, gray seals are known to pup at three or
more colonies in Massachusetts and Maine.
Gray seals are uncommon in Virginia and in the Chesapeake Bay. Only
15 gray seal strandings were documented in Virginia from 1988 through
2013 (Barco and Swingle, 2014). They are rarely found resting on the
rocks around the portal islands of the CBBT from December through April
alongside harbor seals. Seal observation surveys conducted at the CBBT
recorded one gray seal in each of the 2014/2015 and 2015/2016 seasons
while no gray seals were reported during the 2016/2017 and 2017/2018
seasons (Rees et al., 2016, Jones et al., 2018). Sightings have been
reported off Virginia and near the project area during the winter and
spring (Barco 2013; Rees et al., 2016; Jones et al., 2018; Ampela et
al., 2019).
Unusual Mortality Events
An unusual mortality event (UME) is defined under Section 410(6) of
the MMPA as a stranding that is unexpected; involves a significant die-
off of any marine mammal population; and demands immediate response.
Currently, ongoing UME investigations are underway for pinnipeds along
the Northeast coast, and humpback whales along the Atlantic coast.
Northeast Pinniped UME
Since July 2018, elevated numbers of harbor seal and gray seal
mortalities have occurred across Maine, New Hampshire and
Massachusetts. This event has been declared an UME. Additionally, seals
showing clinical signs have been stranding as far south as Virginia,
although not in elevated numbers; therefore, the UME investigation now
encompasses all seal strandings from Maine to Virginia. Lastly, while
take is not proposed for these species in this proposed rule, ice seals
(harp and hooded seals) have also started stranding with clinical
signs, again not in elevated numbers, and those two seal species have
also been added to the UME investigation. Additional information is
available at https://www.fisheries.noaa.gov/new-england-mid-atlantic/marine-life-distress/2018-2020-pinniped-unusual-mortality-event-along.
Atlantic Humpback Whale UME
Since January 2016, elevated humpback whale mortalities have
occurred along the Atlantic coast from Maine through Florida. This
event has been declared an UME. A portion of the whales have shown
evidence of pre-mortem vessel strike; however, this finding is not
consistent across all whales examined, and additional research is
needed. Additional information is available at https://www.fisheries.noaa.gov/national/marine-life-distress/2016-2020-humpback-whale-unusual-mortality-event-along-atlantic-coast.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Current data indicate that not all marine
mammal species have equal hearing capabilities (e.g., Richardson et
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect
this, Southall et al. (2007) recommended that marine mammals be divided
into functional hearing groups based on directly measured or estimated
hearing ranges on the basis of available behavioral response data,
audiograms derived using auditory evoked potential techniques,
anatomical modeling, and other data. Note that no direct measurements
of hearing ability have been successfully completed for mysticetes
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. Marine mammal hearing
groups and their associated hearing ranges are provided in Table 9.
Table 9--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans 7 Hz to 35 kHz.
(baleen whales).
Mid-frequency (MF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
High-frequency (HF) cetaceans 275 Hz to 160 kHz.
(true porpoises, Kogia, river
dolphins, cephalorhynchid,
Lagenorhynchus cruciger & L.
australis).
Phocid pinnipeds (PW) (underwater) 50 Hz to 86 kHz.
(true seals).
Otariid pinnipeds (OW) 60 Hz to 39 kHz.
(underwater) (sea lions and fur
seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on ~65 dB threshold from normalized
composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al. 2007) and PW pinniped (approximation).
[[Page 1605]]
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt,
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Five marine mammal species (three cetacean and two phocid pinniped
species) have the reasonable potential to co-occur with the proposed
construction activities. Please refer to Table 8. Of the cetacean
species that may be present, one is classified as a low-frequency
cetacean (i.e., humpback whale) one is classified as a mid-frequency
cetacean (i.e., bottlenose dolphin), and one is classified as a high-
frequency cetacean (i.e., harbor porpoise).
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section includes a summary and discussion of the ways that
components of the specified activity may impact marine mammals and
their habitat. The Estimated Take section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
and Determination section considers the content of this section, the
Estimated Take section, and the Proposed Mitigation section, to draw
conclusions regarding the likely impacts of these activities on the
reproductive success or survivorship of individuals and how those
impacts on individuals are likely to impact marine mammal species or
stocks.
Description of Sound Sources
The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far. The sound level of an area is defined by the
total acoustical energy being generated by known and unknown sources.
These sources may include physical (e.g., waves, wind, precipitation,
earthquakes, ice, atmospheric sound), biological (e.g., sounds produced
by marine mammals, fish, and invertebrates), and anthropogenic sound
(e.g., vessels, dredging, aircraft, construction).
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.
In-water construction activities associated with the project would
include vibratory pile driving and pile removal, impact pile driving,
jetting, and DTH pile installation. The sounds produced by these
activities fall into one of two general sound types: Impulsive and non-
impulsive. Impulsive sounds (e.g., explosions, gunshots, sonic booms,
impact pile driving) are typically transient, brief (less than one
second), broadband, and consist of high peak sound pressure with rapid
rise time and rapid decay (ANSI 1986; NIOSH 1998; ANSI 2005; NMFS,
2018). Non-impulsive sounds (e.g., aircraft, machinery operations such
as drilling or dredging, vibratory pile driving, and active sonar
systems) can be broadband, narrowband or tonal, brief or prolonged
(continuous or intermittent), and typically do not have the high peak
sound pressure with raid rise/decay time that impulsive sounds do (ANSI
1995; NIOSH 1998; NMFS 2018). 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).
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 sound
pressure levels (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). A DTH hammer is used to place hollow steel piles or casings
by drilling. A DTH hammer is a drill bit that drills through the
bedrock using a pulse mechanism that functions at the bottom of the
hole. This pulsing bit breaks up rock to allow removal of debris and
insertion of the pile. The head extends so that the drilling takes
place below the pile. The sounds produced by DTH hammers were
previously thought to be continuous. However, recent sound source
verification (SSV) monitoring has shown that DTH hammer can create
sound that can be considered impulsive (Denes et al. 2019). Since sound
from DTH activities has both impulsive and continuous components, NMFS
characterizes sound from DTH pile installation as being impulsive when
evaluating potential Level A harassment (i.e., injury) impacts and as
being non-impulsive when assessing potential Level B harassment (i.e.
behavior) effects.
The likely or possible impacts of HRCP's proposed activity on
marine mammals could involve both non-acoustic and acoustic stressors.
Potential non-acoustic stressors could result from the physical
presence of the equipment and personnel; however, any impacts to marine
mammals are expected to primarily be acoustic in nature. Acoustic
stressors include effects of heavy equipment operation during pile
driving and removal.
Acoustic Impacts
The introduction of anthropogenic noise into the aquatic
environment from pile driving and removal is the primary means by which
marine mammals may be harassed from HRCP's specified activity. In
general, animals exposed to natural or anthropogenic sound may
experience physical and psychological effects, ranging in magnitude
from none to severe (Southall et al. 2007). In general, exposure to
pile driving noise has the potential to result in auditory threshold
shifts and behavioral reactions (e.g., avoidance, temporary cessation
of foraging and vocalizing, changes in dive behavior). Exposure to
anthropogenic noise can also lead to non-observable physiological
responses such an increase in stress hormones. Additional noise in a
marine mammal's habitat can mask acoustic cues used by
[[Page 1606]]
marine mammals to carry out daily functions such as communication and
predator and prey detection. The effects of pile driving noise on
marine mammals are dependent on several factors, including, but not
limited to, sound type (e.g., impulsive vs. non-impulsive), the
species, age and sex class (e.g., adult male vs. mom with calf),
duration of exposure, the distance between the pile and the animal,
received levels, behavior at time of exposure, and previous history
with exposure (Wartzok et al. 2004; Southall et al. 2007). Here we
discuss physical auditory effects (threshold shifts) followed by
behavioral effects and potential impacts on habitat.
NMFS defines a noise-induced threshold shift (TS) as a change,
usually an increase, in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS 2018). The amount of
threshold shift is customarily expressed in dB. A TS can be permanent
or temporary. As described in NMFS (2018), there are numerous factors
to consider when examining the consequence of TS, including, but not
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough
duration or to a high enough level to induce a TS, the magnitude of the
TS, time to recovery (seconds to minutes or hours to days), the
frequency range of the exposure (i.e., spectral content), the hearing
and vocalization frequency range of the exposed species relative to the
signal's frequency spectrum (i.e., how an animal uses sound within the
frequency band of the signal; e.g., Kastelein et al. 2014), and the
overlap between the animal and the source (e.g., spatial, temporal, and
spectral).
Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS 2018). Available data from
humans and other terrestrial mammals indicate that a 40 dB threshold
shift approximates PTS onset (see Ward et al. 1958, 1959; Ward 1960;
Miller 1974; Ahroon et al. 1996; Henderson et al. 2008). PTS levels for
marine mammals are estimates, as with the exception of a single study
unintentionally inducing PTS in a harbor seal (Kastak et al. 2008),
there are no empirical data measuring PTS in marine mammals largely due
to the fact that, for various ethical reasons, experiments involving
anthropogenic noise exposure at levels inducing PTS are not typically
pursued or authorized (NMFS 2018).
Temporary Threshold Shift (TTS)--TTS is a temporary, reversible
increase in the threshold of audibility at a specified frequency or
portion of an individual's hearing range above a previously established
reference level (NMFS 2018). Based on data from cetacean TTS
measurements (see Southall et al. 2007), a TTS of 6 dB is considered
the minimum threshold shift clearly larger than any day-to-day or
session-to-session variation in a subject's normal hearing ability
(Schlundt et al. 2000; Finneran et al. 2000, 2002). As described in
Finneran (2015), marine mammal studies have shown the amount of TTS
increases with cumulative sound exposure level (SELcum) in an
accelerating fashion: At low exposures with lower SELcum, the amount of
TTS is typically small and the growth curves have shallow slopes. At
exposures with higher SELcum, the growth curves become steeper and
approach linear relationships with the noise sound exposure level
(SEL).
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in auditory
masking, below). For example, a marine mammal may be able to readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal
is traveling through the open ocean, where ambient noise is lower and
there are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts. We note that reduced hearing sensitivity as
a simple function of aging has been observed in marine mammals, as well
as humans and other taxa (Southall et al. 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without cost.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin, beluga whale (Delphinapterus leucas), harbor
porpoise, and Yangtze finless porpoise (Neophocoena asiaeorientalis))
and five species of pinnipeds exposed to a limited number of sound
sources (i.e., mostly tones and octave-band noise) in laboratory
settings (Finneran 2015). TTS was not observed in trained spotted
(Phoca largha) and ringed (Pusa hispida) seals exposed to impulsive
noise at levels matching previous predictions of TTS onset (Reichmuth
et al. 2016). In general, harbor seals and harbor porpoises have a
lower TTS onset than other measured pinniped or cetacean species
(Finneran 2015). Additionally, the existing marine mammal TTS data come
from a limited number of individuals within these species. No data are
available on noise-induced hearing loss for mysticetes. For summaries
of data on TTS in marine mammals or for further discussion of TTS onset
thresholds, please see Southall et al. (2007), Finneran and Jenkins
(2012), Finneran (2015), and Table 5 in NMFS (2018). Installing piles
requires a combination of impact pile driving and vibratory pile
driving. For this project, these activities would not occur at the same
time and there would be pauses in activities producing the sound during
each day. Given these pauses and that many marine mammals are likely
moving through the ensonified area and not remaining for extended
periods of time, the potential for TS declines.
Behavioral Harassment--Exposure to noise from pile driving and
removal also has the potential to behaviorally disturb marine mammals.
Available studies show wide variation in response to underwater sound;
therefore, it is difficult to predict specifically how any given sound
in a particular instance might affect marine mammals perceiving the
signal. If a marine mammal does react briefly to an underwater sound by
changing its behavior or moving a small distance, the impacts of the
change are unlikely to be significant to the individual, let alone the
stock or population. However, if a sound source displaces marine
mammals from an important feeding or breeding area for a prolonged
period, impacts on individuals and populations could be significant
(e.g., Lusseau and Bejder 2007; Weilgart 2007; NRC 2005).
Disturbance may result in 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.
Pinnipeds may increase their haul out time, possibly to avoid in-water
disturbance (Thorson and Reyff 2006). Behavioral responses to sound are
highly variable and context-specific and any reactions depend on
numerous intrinsic and extrinsic factors (e.g., species, state of
maturity, experience,
[[Page 1607]]
current activity, reproductive state, auditory sensitivity, time of
day), as well as the interplay between factors (e.g., Richardson et al.
1995; Wartzok et al. 2003; Southall et al., 2007; Weilgart 2007; Archer
et al,. 2010). Behavioral reactions can vary not only among individuals
but also within an individual, depending on previous experience with a
sound source, context, and numerous other factors (Ellison et al.
2012), and can vary depending on characteristics associated with the
sound source (e.g., whether it is moving or stationary, number of
sources, distance from the source). In general, pinnipeds seem more
tolerant of, or at least habituate more quickly to, potentially
disturbing underwater sound than do cetaceans, and generally seem to be
less responsive to exposure to industrial sound than most cetaceans.
Please see Appendices B-C of Southall et al. (2007) for a review of
studies involving marine mammal behavioral responses to sound.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble curtains or sediment plumes), or changes in
dive behavior. As for other types of behavioral response, the
frequency, duration, and temporal pattern of signal presentation, as
well as differences in species sensitivity, are likely contributing
factors to differences in response in any given circumstance (e.g.,
Croll et al. 2001; Nowacek et al. 2004; Madsen et al. 2006; Yazvenko et
al. 2007). A determination of whether foraging disruptions incur
fitness consequences would require information on or estimates of the
energetic requirements of the affected individuals and the relationship
between prey availability, foraging effort and success, and the life
history stage of the animal.
Stress responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Seyle 1950; Moberg
2000). In many cases, an animal's first and sometimes most economical
(in terms of energetic costs) response is behavioral avoidance of the
potential stressor. Autonomic nervous system responses to stress
typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg 1987; Blecha
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Hood et al., 1998; Jessop et al., 2003; Krausman et al., 2004;
Lankford et al., 2005). Stress responses due to exposure to
anthropogenic sounds or other stressors and their effects on marine
mammals have also been reviewed (Fair and Becker 2000; Romano et al.,
2002b) and, more rarely, studied in wild populations (e.g., Romano et
al., 2002a). For example, Rolland et al. (2012) found that noise
reduction from reduced ship traffic in the Bay of Fundy was associated
with decreased stress in North Atlantic right whales. These and other
studies lead to a reasonable expectation that some marine mammals will
experience physiological stress responses upon exposure to acoustic
stressors and that it is possible that some of these would be
classified as ``distress.'' In addition, any animal experiencing TTS
would likely also experience stress responses (NRC, 2003), however
distress is an unlikely result of this project based on observations of
marine mammals during previous, similar projects in the area.
Masking--Sound can disrupt behavior through masking, or interfering
with, an animal's ability to detect, recognize, or discriminate between
acoustic signals of interest (e.g., those used for intraspecific
communication and social interactions, prey detection, predator
avoidance, navigation) (Richardson et al., 1995). Masking occurs when
the receipt of a sound is interfered with by another coincident sound
at similar frequencies and at similar or higher intensity, and may
occur whether the sound is natural (e.g., snapping shrimp, wind, waves,
precipitation) or anthropogenic (e.g., pile driving, shipping, sonar,
seismic exploration) in origin. The ability of a noise source to mask
biologically important sounds depends on the characteristics of both
the noise source and the signal of interest (e.g., signal-to-noise
ratio, temporal variability, direction), in relation to each other and
to an animal's hearing abilities (e.g., sensitivity, frequency range,
critical ratios, frequency discrimination, directional discrimination,
age or TTS hearing loss), and existing ambient noise and propagation
conditions. Masking of natural sounds can result when human activities
produce high levels of background sound at frequencies important to
marine mammals. Conversely, if the background level of underwater sound
is high (e.g., on a day with strong wind and high waves), an
anthropogenic sound source would not be detectable as far away as would
be possible under quieter conditions and would itself be masked. The
project area contains numerous, naval, commercial, and recreational
vessels; therefore, it is possible that background underwater sound
levels in the area are elevated, meaning that continuous noise from
sources such as vibratory pile driving would be less likely to cause
disruption of behavioral patterns when detected.
Airborne Acoustic Effects-- Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with pile driving,
pile removal and DTH pile installation that have the potential to cause
behavioral harassment, depending on their distance from pile driving
activities. Cetaceans are not expected to be exposed to airborne sounds
that would result in harassment as defined under the MMPA.
Airborne noise would primarily be an issue for pinnipeds that are
swimming or hauled out near the project site within the range of noise
levels exceeding the acoustic thresholds. We recognize that pinnipeds
in the water could be exposed to airborne sound that may result in
behavioral harassment when looking with their heads above
[[Page 1608]]
water. 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 the area and move
further from the source. However, these animals would previously have
been taken by Level B harassment because of exposure to underwater
sound above the behavioral harassment thresholds, which are, in all
cases, larger than those associated with airborne sound. 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.
Marine Mammal Habitat Effects
HRCP's construction activities could have localized, temporary
impacts on marine mammal habitat by increasing in-water sound pressure
levels and slightly decreasing water quality. Construction activities
are of short duration and would likely have temporary impacts on marine
mammal habitat through increases in underwater sound. Increased noise
levels may affect acoustic habitat (see masking discussion above) and
adversely affect marine mammal prey in the vicinity of the project area
(see discussion below). During impact and vibratory pile driving,
elevated levels of underwater noise would ensonify the project area
where both fish and mammals may occur and could affect foraging
success. Additionally, marine mammals may avoid the area during
construction, however, displacement due to noise is expected to be
temporary and is not expected to result in long-term effects to the
individuals or populations.
A localized increase in turbidity near the seafloor during
construction would occur in the immediate area surrounding the area
where piles are installed (and removed in the case of the temporary
piles). The sediments on the sea floor will be disturbed during pile
driving; however, suspension will be brief and localized and is
unlikely to measurably affect marine mammals or their prey in the area.
In general, turbidity associated with pile installation is localized to
about a 25-ft (7.6-meter) radius around the pile (Everitt et al. 1980).
Cetaceans are not expected to be close enough to the pile driving areas
to experience effects of turbidity, and any pinnipeds could avoid
localized areas of turbidity. Therefore, we expect the impact from
increased turbidity levels to be discountable to marine mammals and do
not discuss it further.
In-Water Construction Effects on Potential Foraging Habitat
The proposed activities would not result in permanent impacts to
habitats used directly by marine mammals except for the actual
footprint of the project. The total seafloor area affected by pile
installation and removal is small compared to the vast foraging area
available to marine mammals in the project area and lower Chesapeake
Bay.
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 we anticipate a rapid return to normal recruitment,
distribution and behavior. Any behavioral avoidance by fish of the
disturbed area would still leave large areas of fish and marine mammal
foraging habitat in the nearby vicinity in the project area and lower
Chesapeake Bay.
In-Water Construction Effects on Potential Prey (Fish)
Sound may affect marine mammals through impacts on the abundance,
behavior, or distribution of prey species (e.g., fish). Marine mammal
prey varies by species, season, and location. Here, we describe studies
regarding the effects of noise on known marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009).
Depending on their hearing anatomy and peripheral sensory structures,
which vary among species, fishes hear sounds using pressure and
particle motion sensitivity capabilities and detect the motion of
surrounding water (Fay et al., 2008). The potential effects of noise on
fishes depends on the overlapping frequency range, distance from the
sound source, water depth of exposure, and species-specific hearing
sensitivity, anatomy, and physiology. Key impacts to fishes may include
behavioral responses, hearing damage, barotrauma (pressure-related
injuries), and mortality.
Fish react to sounds which are especially strong and/or
intermittent low-frequency sounds, and behavioral responses such as
flight or avoidance are the most likely effects. Short duration, sharp
sounds can cause overt or subtle changes in fish behavior and local
distribution. The reaction of fish to noise depends on the
physiological state of the fish, past exposures, motivation (e.g.,
feeding, spawning, migration), and other environmental factors.
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 (e.g., Scholik and Yan,
2001, 2002; Popper and Hastings, 2009). Several studies have
demonstrated that impulse sounds might affect the distribution and
behavior of some fishes, potentially impacting foraging opportunities
or increasing energetic costs (e.g., Fewtrell and McCauley, 2012;
Pearson et al., 1992; Skalski et al., 1992; Santulli et al., 1999;
Paxton et al., 2017). However, some studies have shown no or slight
reaction to impulse sounds (e.g., Wardle et al., 2001; Jorgenson and
Gyselman, 2009; Cott et al., 2012).
SPLs of sufficient strength have been known to cause injury to fish
and fish mortality. However, in most fish species, hair cells in the
ear continuously regenerate and loss of auditory function likely is
restored when damaged cells are replaced with new cells. Halvorsen et
al. (2012a) showed that a TTS of 4-6 dB was recoverable within 24 hours
for one species. Impacts would be most severe when the individual fish
is close to the source and when the duration of exposure is long.
Injury caused by barotrauma can range from slight to severe and can
cause death, and is most likely for fish with swim bladders. Barotrauma
injuries have been documented during controlled exposure to impact pile
driving (Halvorsen et al., 2012b; Casper et al., 2013).
The most likely impact to fish from pile driving activities at the
project areas would be temporary behavioral avoidance of the area. The
duration of fish avoidance of an area after pile driving stops is
unknown, but a rapid return to normal recruitment, distribution and
behavior is anticipated.
In summary, given the relatively small areas being affected, and
the fact that these areas do not include habitat of particularly high
quality or importance, pile driving and removal 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, we
conclude that impacts of the specified activity are not likely to have
more than short-term adverse effects on any prey habitat or populations
of prey species. Further, any impacts to marine mammal habitat are not
expected to result in significant or long-term consequences for
individual marine mammals, or to
[[Page 1609]]
contribute to adverse impacts on their populations.
Estimated Take
This section provides an estimate of the number of incidental takes
proposed for authorization through this LOA, which will inform both
NMFS' consideration of small numbers and the negligible impact
determination.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines harassment as: Any act of
pursuit, torment, or annoyance which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would primarily be by Level B harassment, as noise
generated from in-water pile driving (vibratory and impact) has the
potential to result in disruption of behavioral patterns for individual
marine mammals. There is also some potential for auditory injury (Level
A harassment) to result, primarily for low- and high-frequency species
and phocids because predicted auditory injury zones are larger than for
mid-frequency species. Auditory injury is unlikely to occur for mid-
frequency species. The proposed mitigation and monitoring measures are
expected to minimize the severity of such taking to the extent
practicable.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the take is estimated.
Generally speaking, we estimate take by considering: (1) Acoustic
thresholds above which marine mammals will be behaviorally disturbed or
incur some degree of permanent hearing impairment; (2) the area or
volume of water that will be ensonified above these levels in a day;
(3) the density or occurrence of marine mammals within these ensonified
areas; and, (4) and the number of days of activities. We note that
while these basic factors can contribute to a basic calculation to
provide an initial prediction of takes, additional information that can
qualitatively inform take estimates is also sometimes available (e.g.,
previous monitoring results or average group size). Below, we describe
the factors considered here in more detail and present the proposed
take estimate.
Acoustic Thresholds
NMFS recommends the use of acoustic thresholds that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to experience behavioral disturbance
(equated to Level B harassment) or to incur PTS of some degree (equated
to Level A harassment).
Level B Harassment for non-explosive sources--Though significantly
driven by received level, the onset of behavioral disturbance from
anthropogenic noise exposure is also informed to varying degrees by
other factors related to the source (e.g., frequency, predictability,
duty cycle), the environment (e.g., bathymetry), and the receiving
animals (hearing, motivation, experience, demography, behavioral
context) and can be difficult to predict (Southall et al., 2007,
Ellison et al., 2012). Based on what the available science indicates
and the practical need to use a threshold based on a factor that is
both predictable and measurable for most activities, NMFS uses a
generalized acoustic threshold based on received level to estimate the
onset of Level B harassment. NMFS predicts that marine mammals are
likely to experience behavioral disturbance in a manner we consider
Level B harassment when exposed to underwater anthropogenic noise above
received levels of 120 dB re 1 [mu]Pa (rms) for continuous (e.g.,
vibratory pile-driving, drilling) and above 160 dB re 1 [mu]Pa (rms)
for non-explosive impulsive (e.g., seismic airguns) or intermittent
(e.g., scientific sonar) sources.
HRCP's proposed activity includes the use of continuous (vibratory
pile driving, DTH pile installation) and impulsive (impact pile
driving, DTH pile installation), sources, and therefore the 120 and 160
dB re 1 [mu]Pa (rms) criteria are applicable. Note that the 120 dB
criterion is used for DTH pile installation, as the continuous noise
produced through the activity will produce the largest harassment
isopleths.
Level A harassment for non-explosive sources--NMFS' Technical
Guidance for Assessing the Effects of Anthropogenic Sound on Marine
Mammal Hearing (Version 2.0) (Technical Guidance, 2018) identifies dual
criteria to assess auditory injury (Level A harassment) to five
different marine mammal groups (based on hearing sensitivity) as a
result of exposure to noise from two different types of sources
(impulsive or non-impulsive). As noted previously, HRCP's proposed
activity includes the use of impulsive (impact pile driving, DTH pile
installation) and non-impulsive (vibratory pile driving/removal, DTH
pile installation) sources.
These thresholds are provided in the Table 10 below. The
references, analysis, and methodology used in the development of the
thresholds are described in NMFS 2018 Technical Guidance, which may be
accessed at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 10--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans/.......... Cell 1: Lpk,flat: 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
[[Page 1610]]
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[mu]Pa\2\s. In this Table, thresholds are abbreviated to reflect American National
Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as incorporating
frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is
being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized
hearing range. The subscript associated with cumulative sound exposure level thresholds indicates the
designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and
that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be
exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it
is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into identifying the area ensonified above the
acoustic thresholds, which include source levels and transmission loss
coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the project. Marine
mammals are expected to be affected via sound generated by the primary
components of the project (i.e., vibratory pile driving, vibratory pile
removal, impact pile driving, jetting, and DTH pile installation).
Sound source levels (SSLs) for each method of installation and
removal were estimated using empirical measurements from similar
projects in Norfolk and Little Creek (Craney Island), elsewhere in
Virginia, or outside of Virginia (California, Florida, Washington,
Alaska) (Table 11). It is assumed that jetting will be quieter than
vibratory installation of the same pile size, but data for this
activity are limited; therefore, SSLs for vibratory installation have
been applied to jetting.
DTH pile installation includes drilling (non-impulsive sound) and
hammering (impulsive sound) to penetrate rocky substrates (Denes et al.
2016; Denes et al. 2019; Reyff and Heyvaert 2019). DTH pile
installation was initially thought be a primarily non-impulsive noise
source. However, Denes et al. (2019) concluded from a study conducted
in Virginia, nearby the location for this project, that DTH should be
characterized as impulsive based on Southall et al. (2007), who stated
that signals with a >3 dB difference in sound pressure level in a
0.035-second window compared to a 1-second window can be considered
impulsive. Therefore, DTH pile installation is treated as both an
impulsive and non-impulsive noise source. In order to evaluate Level A
harassment, DTH pile installation activities are evaluated according to
the impulsive criteria. Level B harassment isopleths are determined by
applying non-impulsive criteria and using the 120 dB threshold which is
also used for vibratory driving. This approach ensures that the largest
ranges to effect for both Level A and Level B harassment are accounted
for in the take estimation process.
The source level employed to derive Level B harassment isopleths
for DTH pile installation of all pile sizes was derived from the Denes
et al. (2016) study at Kodiak, Alaska. The median source value for
drilling was reported to be 166 dB RMS.
The source level employed to derive Level A harassment isopleths
for DTH pile installation of piles/holes above 24-inch up to 42-inch in
diameter came from a combination of (whichever higher for given metric)
Reyff and Heyvaert (2019), Denes et al. (2019), and Reyff (2020). For
pile/holes 60-inch in diameter, values were provided by Reyff (Reyff
personal communication) and are shown in Table 11. Note that during
some driving scenarios bubble curtains will be used to reduce sound
source levels by 7 dB from the values recorded by Denes et al. (2019)
at the nearby Chesapeake Bay Bridge Tunnel. These are also noted in
Table 11.
Table 11--Summary of Project Sound Source Levels
[a 10 m]
----------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------
Method and pile type Sound source level at 10 meters Literature source
----------------------------------------------------------------------------------------------------------------
Vibratory Hammer dB rms ........................
----------------------------------------------------------------------------------------------------------------
42-inch steel pile.................... 168 Austin et al. 2016.
----------------------------------------------------------------------------------------------------------------
36-inch steel pile.................... 167 DoN 2015.
----------------------------------------------------------------------------------------------------------------
30-inch steel pile, concrete filled... 167 DoN 2015.
----------------------------------------------------------------------------------------------------------------
24-inch steel pile.................... 161 DoN 2015.
----------------------------------------------------------------------------------------------------------------
16-inch CCA timber pile *............. 162 Caltrans 2015.
----------------------------------------------------------------------------------------------------------------
AZ 700-19 steel sheet pile............ 160 Caltrans 2015.
----------------------------------------------------------------------------------------------------------------
AZ 700-26 steel sheet pile............ 160 Caltrans 2015.
----------------------------------------------------------------------------------------------------------------
Jetting dB rms ........................
----------------------------------------------------------------------------------------------------------------
42-inch steel pile.................... 161 Austin et al. 2016.
----------------------------------------------------------------------------------------------------------------
DTH Pile Installation dB rms dB SEL dB peak ........................
----------------------------------------------------------------------------------------------------------------
30-inch and 36-inch steel pipe piles.. 166 164 196 Denes et al. 2016, 2019;
Reyff and Heyvaert
2019; Reyff 2020.
----------------------------------------------------------------------------------------------------------------
60-inch steel pipe pile............... 166 175 196 Denes et al. 2016; Reyff
pers. comm.
----------------------------------------------------------------------------------------------------------------
[[Page 1611]]
Impact Hammer dB rms dB SEL dB peak ........................
----------------------------------------------------------------------------------------------------------------
36-inch steel pile.................... 193 183 210 Caltrans 2015;
Chesapeake Tunnel Joint
Venture 2018.
----------------------------------------------------------------------------------------------------------------
36-inch steel pile, attenuated **..... 186 176 203 Caltrans 2015;
Chesapeake Tunnel Joint
Venture 2018 +.
----------------------------------------------------------------------------------------------------------------
30-inch steel pile, concrete filled... 195 186 216 DoN 2015.
----------------------------------------------------------------------------------------------------------------
30-inch steel pile, concrete filled, 188 179 209 DoN 2015.
attenuated **.
----------------------------------------------------------------------------------------------------------------
24-inch steel pile.................... 190 177 203 Caltrans 2015.
----------------------------------------------------------------------------------------------------------------
24-inch steel pile, attenuated **..... 183 170 196 Caltrans 2015.
----------------------------------------------------------------------------------------------------------------
54-inch concrete cylinder pile ***.... 187 177 193 MacGillivray et al.
2007.
----------------------------------------------------------------------------------------------------------------
24-inch concrete square pile.......... 176 166 188 Caltrans 2015.
----------------------------------------------------------------------------------------------------------------
Note: It is assumed that noise levels during pile installation and removal are similar. dB = decibel: SEL =
sound exposure level; dB peak = peak sound level; rms = root mean square; DoN = Department of the Navy; CCA =
Chromated Copper Arsenate, Caltrans = California Department of Transportation.
* SSL taken from 12-inch timber piles in Norfolk, Virginia.
** SSLs are a 7 dB reduction from Chesapeake Tunnel Joint Venture 2018 values due to usage of a bubble curtain.
*** SSLs taken from 36-inch concrete square piles, no project specific information provided.
\+\ The primary literature source for 36-inch steel pipe attenuated piles is Caltrans 2015; however, the
Chesapeake Tunnel Joint Venture 2018 is also cited due to the proximity of the project to the HRBT Project.
Simultaneous use of hammers could result in increased SPLs and
harassment zone sizes given the proximity of the component driving
sites and the rules of decibel addition. Impact pile installation is
projected to take place concurrently at 3 to 4 locations and there is
the potential for as many as 7 pile installation locations operating
concurrently. NMFS (2018b) handles overlapping sound fields created by
the use of more than one hammer differently for impulsive (impact
hammer and Level A harassment zones for drilling with a DTH hammer) and
continuous sound sources (vibratory hammer and Level B harassment zones
for drilling with a DTH hammer) (See Table 12). It is unlikely that the
two impact hammers would strike at the same instant, and therefore, the
SPLs will not be adjusted regardless of the distance between impact
hammers. In this case, each impact hammer will be considered to have
its own independent Level A and Level B harassment zones and drilling
with a DTH hammer will be considered to have its own independent Level
A harassment zones. It will be unlikely that more than one DTH hammer
will be used within a day at more than one location; therefore, only
one DTH hammer was included in the multiple hammer calculations for
Level B harassment zones.
When two continuous noise sources, such as vibratory hammers, have
overlapping sound fields, there is potential for higher sound levels
than for non-overlapping sources. The method described below was used
by Washington State Department of Transportation (WSDOT) and has been
used by NMFS (WSDOT 2020).
When two or more vibratory hammers are used simultaneously, and the
isopleth of one sound source encompasses the sound source of another
isopleth, the sources are considered additive and combined using the
following rules (Table 12) for addition of two simultaneous vibratory
hammers, the difference between the two SSLs is calculated, and if that
difference is between 0 and 1 dB, 3 dB are added to the higher SSL; if
difference is between 2 or 3 dB, 2 dB are added to the highest SSL; if
the difference is between 4 to 9 dB, 1 dB is added to the highest SSL;
and with differences of 10 or more decibels, there is no addition.
Table 12--Rules for Combining Sound Levels Generated During Pile Installation
----------------------------------------------------------------------------------------------------------------
Hammer types Difference in SSL Level A harassment zones Level B harassment zones
----------------------------------------------------------------------------------------------------------------
Vibratory, Impact................. Any.................. Use impact zones.......... Use vibratory zone.
Impact, Impact.................... Any.................. Use zones for each pile Use zone for each pile
size and number of size.
strikes.
Vibratory, Vibratory.............. 0 or 1 dB............ Add 3 dB to the higher Add 3 dB to the higher
source level. source level.
2 or 3 dB............ Add 2 dB to the higher Add 2 dB to the higher
source level. source level.
4 to 9 dB............ Add 1 dB to the higher Add 1 dB to the higher
source level. source level.
10 dB or more........ Add 0 dB to the higher Add 0 dB to the higher
source level. source level.
----------------------------------------------------------------------------------------------------------------
When three or more continuous sound sources are used concurrently,
such as vibratory hammers, the three overlapping sources with the
highest SSLs are identified. Of the three highest SSLs, the lower two
are combined using
[[Page 1612]]
the above rules, then the combination of the lower two is combined with
the highest of the three.
It is common for pile installation to start and stop multiple times
as each pile is adjusted and its progress is measured and documented.
For short durations, it is anticipated that multiple hammers could be
in use simultaneously. Following an approach modified from WSDOT in
their Biological Assessment manual and described in Table 13, decibel
addition calculations were carried out for possible combinations of
vibratory installations of 24-, 30-, 36-, and 42-inch steel pipe piles
throughout the Project area.
[GRAPHIC] [TIFF OMITTED] TP08JA21.003
These source levels are used to compute the Level A harassment
zones and to estimate the Level B harassment zones.
Level A Harassment Zones
When the NMFS' Technical Guidance (2016) was published, in
recognition of the fact that ensonified area/volume could be more
technically challenging to predict because of the duration component in
the new thresholds, we developed a User Spreadsheet that includes tools
to help predict a simple isopleth that can be used in conjunction with
marine mammal density or occurrence to help predict takes. We note that
because of some of the assumptions included in the methods used for
these tools, we anticipate that isopleths produced are typically going
to be overestimates of some degree, which may result in some degree of
overestimate of Level A harassment take. However, these tools offer the
best way to predict appropriate isopleths when more sophisticated 3D
modeling methods are not available, and NMFS continues to develop ways
to quantitatively refine these tools, and will qualitatively address
the output where appropriate. For stationary sources such as in-water
pile driving activities during the HRBT project, NMFS User Spreadsheet
predicts the closest distance at which, if a marine mammal remained at
that distance the whole duration of the activity, it would incur PTS.
Inputs used in the User Spreadsheet (Table 14 and Table 15) and the
resulting isopleths are reported below (Table 14). Level A harassment
thresholds for impulsive sound sources (impact pile driving, DTH pile
installation) are defined for both SELcum and Peak SPL, with the
threshold that results in the largest modeled isopleth for each marine
mammal hearing group used to establish the effective Level A harassment
isopleth.
For purposes of estimated take by Level A harassment, NMFS assumed
that the strike rate for impact pile installation was 50 percent of the
estimated number of strikes displayed in Table 14 and 15. Similarly,
for vibratory driving NMFS assumed that the driving time for each pile
was 50 percent of the estimated total. For the DTH hammer calculations,
Reyff and Heyvaert 2019 identified a strike rate of 10 Hz. This was
also reduced by 50 percent to 5 Hz which to achieve the same 50 percent
Level A harassment reduction as was done for impact and vibratory
driving. Strikes per Pile values were not altered when calculating
Level A harassment zones for DTH pile installation.
Since the marine mammals proposed for authorization are highly
mobile, it is unlikely that an animal would remain within an
established Level A harassment zone for the entire duration or number
of strikes associated with installation or removal of a specified
number of piles throughout a given day. This was done to provide more
realistic take estimates by Level A harassment. NMFS applied this
reduction across all pile sizes, types, and installation/removal
methods as shown in Tables 14 and 15. Additionally, note that under
some driving scenarios a 7 dB attenuation was applied to impact
installation of 24-inch steel, 30-inch Steel, and 36-inch steel due to
use of bubble curtains as shown in Table 14.
The calculated Level A isopleths for different size pile and
driving types are shown in Tables 16-18.
BILLING CODE 3510-22-P
[[Page 1613]]
[GRAPHIC] [TIFF OMITTED] TP08JA21.004
[[Page 1614]]
[GRAPHIC] [TIFF OMITTED] TP08JA21.005
BILLING CODE 3510-22-C
[[Page 1615]]
Table 15--User Spreadsheet Input Parameters Used for Calculating Level A Harassment Isopleths for Drilling With
a DTH Hammer *
----------------------------------------------------------------------------------------------------------------
30-inch steel, 36-inch steel 60-inch steel
concrete filled ---------------------------------
Model parameter -------------------
DTH DTH DTH
----------------------------------------------------------------------------------------------------------------
Spreadsheet Tab............................................ E.2 E.2 E.2
Weighting Factor Adjustment (kilohertz).................... 2 2 2
SELss (LE, p, single strike) at 10 meters.................. 164 164 175
Lp, 0-pk at 10 meters...................................... 196 196 196
Number of piles per day.................................... 6 2 3
Duration to drive a pile (minutes)......................... 120 120 120
Transmission loss coefficient.............................. 15 15 15
Distance from source (meters).............................. 10 10 10
Estimated Number of Strikes per 24-hour period............. 432,000 144,000 216,000
50% of Strikes per 24-hour period.......................... 216,000 72,000 108,000
Strike rate (Hz) average strikes per second................ 10 10 10
50% of Strike rate (Hz) average strikes per second......... 5 5 5
----------------------------------------------------------------------------------------------------------------
* To provide a more realistic estimate of take by Level A harassment, NMFS assumes that an animal would occur
within the vicinity of the construction activity for 50 percent of the pile installation and removal time,
which equates to 50 percent of the piles planned for installation and removal. HRCP has implemented this
reduction across all pile sizes, types, and installation and removal methods. For drilling with a DTH hammer
installation, the strike rate (Hz) was reduced by half to accomplish the reduction. A 10 Hz strike rate was
identified from Reyff and Heyvaert 2019 which was then reduced by 50% to 5 Hz to accomplish the 50% Level A
reduction.
Table 16--Calculated Distances to Level A Harassment Isopleths During Vibratory Installation, and Vibratory Removal and Jetting Installation With No
Attenuation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment isopleth distance Level A Harassment isopleth areas
(meters) (km\2\)
Minutes per Number of -----------------------------------------------------------------------------
Project component Pile size/type pile (reduced piles per Cetaceans Pinnipeds Cetaceans Pinnipeds
by half) day -----------------------------------------------------------------------------
LF MF HF PW LF MF HF PW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Hammer
North Trestle
--------------------------------------------------------------------------------------------------------------------------------------------------------
Moorings.................... 42-inch Pipe, 15 6 27 3 39 16 <0.01
Steel.
Template Piles.............. 36-inch Pipe, 2.5 8 9 1 13 5 <0.01
Steel.
North Shore Work Trestle, 36-inch Pipe, 25 2 16 2 23 10 <0.01
Jump Trestle, Work Trestle, Steel.
Demolition Trestle.
Moorings.................... 24-inch Pipe, 15 6 9 1 14 6 <0.01
Steel.
North Shore Abutment........ AZ 700-19 15 10 11 1 16 7 <0.01
Sheet, Steel.
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Island
--------------------------------------------------------------------------------------------------------------------------------------------------------
Moorings.................... 42-inch Pipe, 15 6 27 3 39 16 <0.01
Steel.
Hampton Creek Approach Existing, 36- 25 1 10 1 15 6 <0.01
Channel Marker. inch Pipe,
Steel.
North Island Expansion...... AZ 700-26 15 10 11 1 16 7 <0.01
Sheet, Steel.
North Island Abutment....... AZ 700-19
Sheet, Steel.
South Island Abutment....... AZ 700-19 15 10 11 1 16 7 <0.01
Sheet, Steel.
South Island Expansion...... AZ 700-26
Sheet, Steel.
Settlement Reduction Piles.. 24-inch Pipe, 30 6 15 2 21 9
Steel.
Deep Foundation Piles....... 30-inch Pipe, 30 6 36 4 53 22
Steel,
Concrete
Filled.
TBM Platform................ 36-inch Pipe, 30 2 18 2 26 11
Steel.
Conveyor Trestle............ 36-inch Pipe, 25 3 20 2 30 13
Steel.
Moorings.................... 42-inch Pipe, 15 6 27 3 39 16 <0.01
Steel.
Template Piles.............. 36-inch Pipe, 2.5 16 14 2 20 8 <0.01
Steel.
--------------------------------------------------------------------------------------------------------------------------------------------------------
South Trestle
--------------------------------------------------------------------------------------------------------------------------------------------------------
Template Piles.............. 36-inch Pipe, 2.5 8 9 1 13 5 <0.01
Steel.
Moorings, Casings........... 42-inch Pipe, 15 6 27 3 39 16 <0.01
Steel.
Work Trestle, Jump Trestle, 36-inch Pipe, 25 2 16 2 23 10
Demolition Trestle, Steel.
Temporary MOT Trestle.
Moorings.................... 24-inch Pipe, 15 6 9 1 14 6
Steel.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Willoughby Bay
--------------------------------------------------------------------------------------------------------------------------------------------------------
Moorings.................... 24-inch Pipe, 15 6 9 1 14 6 <0.01
Steel.
Work Trestle, Jump Trestle.. 36-inch Pipe, 25 2 16 2 23 10
Steel.
Moorings (Safe Haven)....... 42-inch Pipe, 15 6 27 3 39 16 <0.01
Steel.
Casing...................... 42-inch Pipe, 15 6 27 3 39 16 <0.01
Steel.
Template Piles.............. 36-inch Pipe, 2.5 8 9 1 13 5 <0.01
Steel.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Willoughby Spit Laydown Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
Finger Piers on Timber Piles 16-inch CCA, 15 4 8 1 12 5 <0.01
Timber.
Dock on Spuds, Dock on Piles 36-inch Pipe, 25 3 20 2 30 13 <0.01
Steel.
Template Piles.............. 36-inch Pipe, 2.5 16 14 2 20 8 <0.01
Steel.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Jetting
Willoughby Bay
--------------------------------------------------------------------------------------------------------------------------------------------------------
Casing...................... 42-inch Pipe, 15 1 3 1 4 2 <0.01
Steel.
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 1616]]
Table 17--Calculated Distances to Level A Harassment Isopleths During Impact Installation and DTH Pile Installation With No Attenuation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment isopleth distance Level A harassment isopleth areas
Number of (meters) (km\2\)
strikes per Number of -----------------------------------------------------------------------------
Project component Pile size/type pile or strike piles per Cetaceans Pinnipeds Cetaceans Pinnipeds
rate* (reduced day -----------------------------------------------------------------------------
by half) LF MF HF PW LF MF HF PW
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Trestle
--------------------------------------------------------------------------------------------------------------------------------------------------------
Permanent Piles............. 54-inch Pipe, 1,050 1 411 15 490 220 0.53 <0.001 0.75 0.15
Concrete
Cylinder.
Work Trestle, Jump Trestle, 36-inch Pipe, 20 2 117 5 140 63 0.04 <0.001 0.06 0.01
Demolition Trestle. Steel.
--------------------------------------------------------------------------------------------------------------------------------------------------------
South Island
--------------------------------------------------------------------------------------------------------------------------------------------------------
Settlement Reduction Piles.. 24-inch Pipe, 20 6 97 4 116 52 0.02 <0.001 0.03 0.01
Steel.
Deep Foundation Piles....... 30-inch Pipe, 20 6 386 14 459 207 0.35 <0.001 0.49 0.10
Steel,
Concrete
Filled.
--------------------------------------------------------------------------------------------------------------------------------------------------------
South Trestle
--------------------------------------------------------------------------------------------------------------------------------------------------------
Work Trestle, Jump Trestle, 36-inch Pipe, 20 2 117 5 140 63 0.04 <0.001 0.06 0.01
Demolition Trestle, Steel.
Temporary MOT Trestle.
Permanent Piles............. 54-inch Pipe, 1,050 1 411 15 490 220 0.53 <0.001 0.75 0.15
Concrete
Cylinder.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Willoughby Bay
--------------------------------------------------------------------------------------------------------------------------------------------------------
Work Trestle, Jump Trestle.. 36-inch Pipe, 20 2 117 5 140 63 0.04 <0.001 0.06 0.01
Steel.
Permanent Piles............. 24-inch Pipe, 1,050 1 76 3 91 41 0.02 <0.001 0.03 <0.01
Concrete
Square.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Willoughby Spit Laydown Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dock on Spuds, Dock on Piles 36-inch Pipe, 20 3 154 6 183 82 0.12 0.09 <0.001 0.03
Steel.
--------------------------------------------------------------------------------------------------------------------------------------------------------
DTH Pile Installation *
North Trestle
--------------------------------------------------------------------------------------------------------------------------------------------------------
Work Trestle, Jump Trestle, 36-inch Pipe, 36,000 2 936 34 1,115 501 1.81 <0.01 2.27 0.78
Demolition Trestle. Steel.
Casing...................... 60-inch Pipe, 36,000 3 6,633 236 7,901 3,550 34.04 0.18 43.75 13.03
Steel.
--------------------------------------------------------------------------------------------------------------------------------------------------------
South Island
--------------------------------------------------------------------------------------------------------------------------------------------------------
Deep Foundation Piles....... 30-inch Pipe, 36,000 6 1,946 70 2,318 1,042 8.28 <0.01 11.30 2.49
Steel,
Concrete
Filled.
--------------------------------------------------------------------------------------------------------------------------------------------------------
South Trestle
--------------------------------------------------------------------------------------------------------------------------------------------------------
Work Trestle, Jump Trestle, 36-inch Pipe, 36,000 2 936 34 1,115 501 2.67 <0.01 3.67 0.79
Temporary MOT Trestle, Steel.
Demolition Trestle.
Casing...................... 60-inch Pipe, 36,000 3 6,633 236 7,901 3,550 77.50 0.18 102.16 27.12
Steel.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* For DTH Hammer calculations, a 10 Hz strike rate was identified from Reyff and Heyvaert 2019 which was then reduced by 50% to 5 Hz to accomplish the
50% Level A harassment reduction. Strikes per Pile values were not reduced for DTH methods.
Table 18--Calculated Distances to Level A Harassment Isopleths During Impact Installation With Attenuation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment isopleth distance Level A harassment isopleth areas
Number of (meters) (km\2\)
strikes per Number of -----------------------------------------------------------------------------
Project component Pile size/type pile (reduced piles per Cetaceans Pinnipeds Cetaceans Pinnipeds
by half) day -----------------------------------------------------------------------------
LF MF HF PW LF MF HF PW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Hammer
South Island
--------------------------------------------------------------------------------------------------------------------------------------------------------
Settlement Reduction Piles.. 24-inch Pipe, 20 6 33 2 40 18 <0.01
Steel.
----------------------------------------------------------------------------------------------------------
Deep Foundation Piles....... 30-inch Pipe, 20 6 132 5 157 71 0.04 <0.001 0.06 0.01
Steel,
Concrete
Filled.
--------------------------------------------------------------------------------------------------------------------------------------------------------
South Trestle
--------------------------------------------------------------------------------------------------------------------------------------------------------
Temporary MOT Trestle....... 36-inch Pipe, 20 2 40 2 48 22 <0.001 0.007 0.002
Jump Trestle................ Steel.
Work Trestle................
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level B Harassment Zones
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
TL = transmission loss in dB
B = transmission loss coefficient; for practical spreading equals 15
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement
The recommended TL coefficient for most nearshore environments is
the practical spreading value of 15. This value results in an expected
propagation environment that would lie between spherical and
cylindrical spreading loss conditions, which is the most
[[Page 1617]]
appropriate assumption for HRCP's proposed activity.
Using the practical spreading model, HRCP determined underwater
noise would fall below the behavioral effects threshold of 120 dB rms
for marine mammals at a maximum radial distance of 15,849 m for
vibratory pile driving of 42- and 36-inch diameter piles. Other
activities including impact driving and vibratory installation sheet
piles have smaller Level B harassment zones. All Level B harassment
isopleths are reported in Table 19 below. It should be noted that based
on the geography of the project area, and pile driving locations, in
many cases sound will not reach the full distance of the Level B
harassment isopleth. The radial distances provided in Table 19 and
Table 20 are shown as calculated. However, the land areas presented in
these tables take into account truncation by various land masses in the
project area and only shows the in-water ensonified area.
Table 19--Distances to Level B Harassment Isopleths for Different Pile Sizes and Types and Methods of
Installation and Removal With No Attenuation
----------------------------------------------------------------------------------------------------------------
Level B Level B area
Location and component Method and pile type isopleth (m), unattenuated
unattenuated (km\2\)
----------------------------------------------------------------------------------------------------------------
Vibratory Hammer (Level B Isopleth = 120 dB)
North Trestle
----------------------------------------------------------------------------------------------------------------
Moorings.................................. 42-inch steel piles............... 15,849 96.78
Template Piles............................ 36-inch steel piles............... 13,594 85.53
Demolition Trestle........................ 36-inch steel piles............... 13,594 85.53
North Shore Work Trestle.................. 36-inch steel piles............... 13,594 85.53
Jump Trestle.............................. 36-inch steel piles............... 13,594 85.53
Work Trestle.............................. 36-inch steel piles............... 13,594 85.53
Moorings.................................. 24-inch steel piles............... 5,412 25.34
North Shore Abutment...................... AZ 700-19 steel sheet piles....... 4,642 19.81
----------------------------------------------------------------------------------------------------------------
North Island
----------------------------------------------------------------------------------------------------------------
Moorings North............................ 42-inch steel piles............... 15,849 103.86
Moorings South............................ 42-inch steel piles............... 15,849 201.04
Hampton Creek Approach Channel Marker..... 36-inch steel pile................ 13,594 93.99
North Island Expansion North.............. AZ 700-26 steel sheet piles....... 4,642 26.06
North Island Expansion South.............. AZ 700-26 steel sheet piles....... 4,642 36.73
North Island Abutment North............... AZ 700-19 steel sheet piles....... 4,642 26.06
North Island Abutment South............... AZ 700-19 steel sheet piles....... 4,642 36.73
----------------------------------------------------------------------------------------------------------------
South Island
----------------------------------------------------------------------------------------------------------------
Moorings.................................. 42-inch steel piles............... 15,849 246.86
Template Piles............................ 36-inch steel piles............... 13,594 81.75
TBM Platform.............................. 36-inch steel piles............... 13,594 81.75
Conveyor Trestle.......................... 36-inch steel piles............... 13,594 81.75
Deep Foundation Piles..................... 30-inch steel piles, concrete 13,594 194.04
filled.
Settlement Reduction Piles................ 24-inch steel piles............... 5,412 45.10
South Island Expansion.................... AZ 700-26 steel sheet piles....... 4,642 34.69
South Island Abutment..................... AZ 700-19 steel sheet piles....... 4,642 34.69
----------------------------------------------------------------------------------------------------------------
South Trestle
----------------------------------------------------------------------------------------------------------------
Moorings, Casings......................... 42-inch steel piles............... 15,849 305.30
Template Piles............................ 36-inch steel piles............... 13,594 235.60
Temporary MOT Trestle..................... 36-inch steel piles............... 13,594 235.60
Jump Trestle.............................. 36-inch steel piles............... 13,594 235.60
Work Trestle.............................. 36-inch steel piles............... 13,594 235.60
Demolition Trestle........................ 36-inch steel piles............... 13,594 235.60
Moorings.................................. 24-inch steel piles............... 5,412 55.87
----------------------------------------------------------------------------------------------------------------
Willoughby Bay
----------------------------------------------------------------------------------------------------------------
Moorings (Safe Haven)..................... 42-inch steel piles............... 15,849 5.52
Moorings.................................. 42-inch steel piles............... 15,849 5.52
Casing.................................... 42-inch steel piles............... 15,849 5.52
Template Piles............................ 36-inch steel piles............... 13,594 5.52
Work Trestle.............................. 36-inch steel piles............... 13,594 5.52
Jump Trestle.............................. 36-inch steel piles............... 13,594 5.52
Moorings.................................. 24-inch steel piles............... 5,412 5.52
----------------------------------------------------------------------------------------------------------------
Willoughby Spit Laydown Area
----------------------------------------------------------------------------------------------------------------
Template Piles............................ 36-inch steel piles............... 13,594 74.45
Dock on Spuds............................. 36-inch steel piles............... 13,594 74.45
Dock on Piles............................. 36-inch steel piles............... 13,594 74.45
[[Page 1618]]
Finger Piers.............................. 16-inch CCA timber piles.......... 6,310 40.62
----------------------------------------------------------------------------------------------------------------
DTH Pile Installation (Level B Isopleth = 120 dB)
----------------------------------------------------------------------------------------------------------------
North Trestle Casings..................... 60-inch steel piles............... 11,659 72.28
North Trestle Work Trestle, Jump Trestle, 36-inch steel piles............... 11,659 72.28
Demolition Piles, Templates.
South Island Deep Foundation Piles........ 30-inch steel piles, concrete 11,659 152.79
filled.
South Trestle Casings..................... 60-inch steel piles............... 11,659 184.12
South Trestle Work Trestle, Jump Trestle, 36-inch steel piles............... 11,659 14.12
Demolition Trestle, Temporary MOT
Trestle, Templates.
Willoughby Bay Templates.................. 36-inch steel piles............... 11,659 5.52
----------------------------------------------------------------------------------------------------------------
Jetting (Level B Isopleth = 120 dB)
Willoughby Bay
----------------------------------------------------------------------------------------------------------------
Casing.................................... 42-inch steel piles............... 5,412 5.52
----------------------------------------------------------------------------------------------------------------
Impact Hammer (Level B Isopleth = 160 dB)
North Trestle
----------------------------------------------------------------------------------------------------------------
Permanent Piles........................... 54-inch concrete cylinder piles... 631 1.14
Work Trestle.............................. 36-inch steel piles............... 1,585 3.81
Jump Trestle.............................. 36-inch steel piles............... 1,585 3.81
Demolition Trestle........................ 36-inch steel piles............... 1,585 3.81
----------------------------------------------------------------------------------------------------------------
South Island
----------------------------------------------------------------------------------------------------------------
Deep Foundation Piles..................... 30-inch steel piles, concrete 2,154 9.91
filled.
Settlement Reduction Piles................ 24-inch steel piles............... 1,000 2.29
----------------------------------------------------------------------------------------------------------------
South Trestle
----------------------------------------------------------------------------------------------------------------
Permanent Piles........................... 54-inch concrete cylinder piles... 631 1.25
Work Trestle.............................. 36-inch steel piles............... 1,585 6.84
Jump Trestle.............................. 36-inch steel piles............... 1,585 6.84
Temporary MOT Trestle..................... 36-inch steel piles............... 1,585 6.84
Demolition Trestle........................ 36-inch steel piles............... 1,585 6.84
----------------------------------------------------------------------------------------------------------------
Willoughby Bay
----------------------------------------------------------------------------------------------------------------
Permanent Piles........................... 24-inch concrete cylinder piles... 117 0.04
Work Trestle.............................. 36-inch steel piles............... 1,585 3.15
Jump Trestle.............................. 36-inch steel piles............... 1,585 3.15
----------------------------------------------------------------------------------------------------------------
Willoughby Spit Laydown Area
----------------------------------------------------------------------------------------------------------------
Dock on Spuds............................. 36-inch steel piles............... 1,585 6.03
Dock on Piles............................. 36-inch steel piles............... 1,585 6.03
----------------------------------------------------------------------------------------------------------------
Table 20--Distances to Level B Harassment Isopleths for Installation and Removal of Steel Pipe Piles With
Attenuation Bubble Curtain
----------------------------------------------------------------------------------------------------------------
Level B Level B area
Location and component Method and pile type isopleth (m), attenuated
attenuated (km\2\)
----------------------------------------------------------------------------------------------------------------
Impact Hammer (Level B Isopleth = 160 dB)
South Island
----------------------------------------------------------------------------------------------------------------
Deep Foundation Piles..................... 30-inch steel piles, concrete 736 1.25
filled.
Settlement Reduction Piles................ 24-inch steel piles............... 341 0.27
----------------------------------------------------------------------------------------------------------------
South Trestle
----------------------------------------------------------------------------------------------------------------
Temporary MOT Trestle, Work Trestle, Jump 36-inch steel piles............... 541 0.68
Trestle.
----------------------------------------------------------------------------------------------------------------
[[Page 1619]]
The daily duration in which more than one vibratory hammer or DTH
pile installation could occur is difficult to predict and quantify. As
noted previously, DTH pile installation is considered by NMFS to be
both impulsive and continuous. Therefore, decibel addition will not be
used to calculate Level A harassment zones during concurrent DTH pile
installation activities. The Level A harassment zones for each DTH
activity will be based on a single DTH hammer. To simplify
implementation of Level A harassment zones for use of more than one
vibratory hammer within a day and/or during simultaneous use of
multiple vibratory hammers with overlapping isopleths, whether at a
single site or multiple sites, Level A harassment zone sizes were
calculated for the longest anticipated duration of the largest pile
sizes that could be installed within a day. For example, if 18 42-inch
steel pipe piles were installed with a vibratory hammer on a single day
by multiple hammers with overlapping sound fields, the Level A
harassment zone for each of the functional hearing groups likely to be
present near the project area would remain smaller than 100 meters as
shown in Table 21 with the largest Level A harassment zone being 81 m
for harbor porpoises. However, it is highly unlikely that a harbor
porpoise could accumulate enough sound from the installation of
multiple piles in multiple locations for the duration required to meet
the calculated Level A harassment threshold. Furthermore, installation
of 18 42-inch steel pipe piles likely represents an unrealistic level
of efficiency that will not be achieved in the field. Other
combinations of pile sizes and numbers would result in Level A
harassment zones smaller than 100 meters. To be precautionary, shutdown
zones outlined in Table 21 for each species will be implemented for
each vibratory hammer on days when it is anticipated that multiple
vibratory hammers will be used, whether at a single or multiple sites.
This mitigation measure would also minimize the need for onsite
coordination among project sites and components.
Table 21--Distances to Level A Harassment Isopleths for Installation of 42-Inch Piles by Multiple Vibratory Hammers
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment isopleth distance (meters)
-------------------------------------------------------
Pile size/type Minutes per pile Number of piles Cetaceans Pinnipeds
(reduced by half) per day -------------------------------------------------------
LF MF HF PW
--------------------------------------------------------------------------------------------------------------------------------------------------------
42-inch Pipe, Steel...................................... 15 18 55 5 81 33
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: LF = Low-frequency; MF = Mid-frequency; HF = High frequency; PW = Phocids in water. Table does not stipulate the number of active vibratory
hammers, as Level A effects are cumulative. The piles per day could be split between multiple hammers and not affect the size of Level A zones.
The size of the Level B harassment zone during concurrent operation
of multiple vibratory hammers will depend on the combination of sound
sources due to decibel addition of multiple hammers producing
continuous noise. The distances to Level B harassment isopleths during
simultaneous installation of piles using two or more vibratory hammers
is shown in Table 22. As noted previously, pile installation often
involves numerous stops and starts of the hammer for each pile.
Therefore, decibel addition is applied only when the adjacent
continuous sound sources experience overlapping sound fields, which
generally requires close proximity of driving locations. Furthermore,
it is expected to be a rare event when three or more 30-, 36-, or 42-
inch piles are being installed simultaneously with vibratory hammers.
Table 22--Distances to Level B Harassment Isopleths for Multiple Hammer
Additions
------------------------------------------------------------------------
Distance to level
Combined SSL (dB) B isopleth
(meters)
------------------------------------------------------------------------
164.................................................. 8,577
165.................................................. 10,000
166.................................................. 11,659
167.................................................. 13,594
168.................................................. 15,849
169.................................................. 18,478
170.................................................. 21,544
171.................................................. 25,119
172.................................................. 29,286
173.................................................. 34,145
------------------------------------------------------------------------
Marine Mammal Occurrence and Take Calculation and Estimation
In this section we provide the information about the presence,
density, or group dynamics of marine mammals that will inform the take
calculations. We describe how the information provided above is brought
together to produce a quantitative take estimate.
Humpback Whale
While humpback whales are observed near the mouth of the Chesapeake
Bay and the nearshore waters of Virginia during winter and spring
months, they are relatively rare in the project area. Density data for
this species within the project vicinity do not exist or were not
calculated because sample sizes were too small to produce reliable
estimates of density. Humpback whale sighting data collected by the
U.S. Navy near Naval Station Norfolk and Virginia Beach from 2012 to
2015 (Table 22) (Engelhaupt et al. 2014, 2015, 2016) and in the mid-
Atlantic (including the Chesapeake Bay) from 2015 to 2019 (Table 23)
(Aschettino et al. 2015, 2016, 2017a, 2018, 2019) did not produce high
enough sample sizes to calculate densities, or survey data were not
collected during systematic line-transect surveys. However, humpback
whale densities have been calculated for populations off the coast of
New Jersey, resulting in a density estimate of 0.000130 animals per
square kilometer or one humpback whale within the area (off the coast
of New Jersey) on any given day of the year (Whitt et al. 2015). In the
project area, a similar density may be expected, although the project
area is much smaller. Aschettino et al. (2018) observed and tracked two
individual humpback whales in the Hampton Roads (in the James River)
area of the project area and over the 5-year project period (2015-
2019), tracked 12 individual humpback whales west of the CBBT (Movebank
2020). Based on these data, and the known movement of humpback whales
from November through April at the mouth of the Chesapeake Bay, HRCP
requested two takes every month from May to October and three to four
each month from November through April for the
[[Page 1620]]
duration of in-water pile installation and removal. NMFS concurs with
the request and therefore, is proposing to authorize a total of 172
takes of humpback whales over the 5-year Project period (Table 24). The
largest Level A harassment zone of 6,633 meters for LF cetaceans is
associated with drilling with a DTH installation of 60-inch steel pipe
piles (casings) (Table 17). It is unlikely but possible that a humpback
whale could enter this area. Therefore, HRCP requested and NMFS is
proposing to authorize eight humpback whale takes by Level A harassment
(2 per year excluding Year 5), 35 Level B harassment takes each year
for Years 1-4, and 24 Level B harassment takes for Year 5 (Table 24).
Table 23--Summary of Individual Humpback Whale Sightings by Month From 2012 to 2019 in the Chesapeake Bay
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Engelhaupt surveys Aschettino surveys
Month ---------------------------------------------------------------------------------------------------------------------------------
2012 2013 2014 2015 2015 2016 2017 2018 2019 Total
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
January....................................................... ........... 0 0 7 56 43 106 1 30 243
February...................................................... ........... 0 0 0 5 30 84 0 32 151
March......................................................... ........... ........... ........... 0 0 10 7 0 1 18
April......................................................... ........... 2 1 0 0 ........... ........... ........... 1 4
May........................................................... ........... 0 1 0 0 1 ........... ........... 4 6
June.......................................................... ........... ........... 0 ........... ........... ........... ........... ........... ........... 0
July.......................................................... ........... 0 0 0 ........... ........... ........... 1 ........... 1
August........................................................ ........... 0 ........... 0 ........... ........... ........... ........... ........... 0
September..................................................... 0 1 0 ........... ........... ........... ........... ........... ........... 1
October....................................................... 0 0 0 ........... ........... ........... 2 ........... ........... 2
November...................................................... 0 0 0 ........... ........... 21 8 0 ........... 29
December...................................................... ........... ........... 9 ........... 42 30 21 11 ........... 113
---------------------------------------------------------------------------------------------------------------------------------
Total..................................................... 0 3 11 7 103 135 228 13 68 568
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
* Source: Engelhaupt et al. 2014, 2015, 2016 (2012-2015 inshore survey data only; not dedicated humpback whale surveys); Aschettino et al. 2015, 2016, 2017a, 2018, 2019 (2015-2019). Monthly
survey data from the 2019-2020 season have not been published; however, Aschettino et al. 2020b reported that during the 2019/2020 field season, which began 21 December 2019 and concluded 27
March 2020, resulted in 44 humpback whale sightings of 60 individuals.
[GRAPHIC] [TIFF OMITTED] TP08JA21.006
Bottlenose Dolphin
The total estimated number of takes for bottlenose dolphins in the
Project area was estimated using a combined approach of daily sighting
rates and density methods from conventional line-transect vessel
surveys near Naval Station Norfolk and adjacent areas near Virginia
Beach, Virginia, from August 2012 through August 2015 (Engelhaupt et
al. 2016).
HRCP estimated potential exposure using daily sighting data for
areas west of the HRBT area and within the Core Monitoring Area (shown
in Figure 11-1 in the LOA application) and used seasonal densities of
bottlenose dolphins from Engelhaupt et al. (2016) for areas northeast
of the HRBT Project and outside the Core Monitoring Area. The Core
Monitoring Area will encompass the area south of the HRBT and north of
the Hampton Roads Monitor-Merrimac Memorial Bridge-Tunnel (Interstate
664) with observers positioned at key areas to monitor the entire
geographic area between the bridges. This is the area that will be
ensonified during most of the pile installation and removal activities.
Depending on placement, the observers will be able to view west/
southwest towards Batten Bay and the mouth of the Nansemond River. The
largest ensonified southwest radii extend to the south into the James
and Nansemond rivers, areas where marine mammal abundance is
anticipated to be low and approaching zero. Towards the northeast
direction, the largest of the multiple hammer zones may reach beyond
the Chesapeake Bay Bridge and Tunnel. However, concurrent vibratory
installation of three or more 30-, 36-, or 42-inch piles will occur
infrequently.
This approach also factored in the number of days of pile
installation and removal, which is estimated to be 312 days per year
for Years 1-4 and 181 days for Year 5. Due to the complex schedule and
the inexact timeline in
[[Page 1621]]
which parts of the project may be completed ahead of or behind
schedule, trying to quantify the exact number of days certain isopleths
will be active for the purposes of take estimation is infeasible.
However, these calculations reflect the best available data for the
areas in and around the Project and represent a conservative estimate
of potential exposure based on reasonable assumptions.
Sighting rates (numbers of dolphins per day) were determined for
each of the four seasons from observations located in the inshore
Chesapeake Bay zone (the Chesapeake Bay waters near Naval Station
Norfolk) which were used to estimate potential exposure west of the
project site and within the Core Monitoring Area. Sightings per season
ranged from 5 in spring to 24 in fall while no bottlenose dolphins were
sighted in the winter months in this inshore area (Table 25). Note that
the winter sighting total of 0 was a result of truncating winter survey
data to only include sighting data within the vicinity of the project
location. Bottlenose dolphin abundance was highest in the fall, (24
sightings representing 245 individuals), followed by the spring (n =
156), and summer (n = 115). This data was utilized to calculate the
number of dolphins per day that could be anticipated to occur in the
project area during each season and year. The surveyed width for these
surveys was two nautical miles, which encompasses the areas ensonified
within the Core Monitoring Area during pile installation and removal
(HDR-Mott MacDonald 2020). The number of anticipated days of in-water
pile installation and removal for each month was multiplied by the
average daily sighting rate estimate of the number of dolphins per
month that could be exposed to project noise within the Core Monitoring
Area. For the majority of piles being installed and/or removed, the
ensonified area is constrained by surrounding land features and does
not extend out into Chesapeake Bay. For piles with constrained sound
fields, this method is sufficient to calculate potential exposure.
Table 25 depicts values in the average dolphins sighted per day
column that are from within the Core Monitoring Area, which is smaller
and closer to the river mouth. Values in the seasonal density column
(individuals per km\2\) are from outside the Core Monitoring Area which
is farther out in the Bay and where there are likely to be more
dolphins.
Table 25--Average Daily Sighting Rates and Seasonal Densities of Bottlenose Dolphins Within the Project Area
----------------------------------------------------------------------------------------------------------------
Average number of Seasonal density
Number of dolphins sighted outside core
Season sightings per per day within core monitoring area
season monitoring area (individuals/km\2\)
----------------------------------------------------------------------------------------------------------------
Spring, March-May..................................... 5 17.33 1.00
Summer, June-August................................... 14 16.43 3.55
Fall, September-November.............................. 24 27.22 3.88
Winter, December-February............................. 0 0.00 0.63
----------------------------------------------------------------------------------------------------------------
Source: Engelhaupt et al. 2016.
For each month and year, the average area within the Level B
harassment zones and outside the Core Monitoring Area was calculated
and used to estimate potential exposure east of the project site and
outside the Core Monitoring Area. The weighted average area within the
relevant Level B harassment zones outside the Core Monitoring Area was
used to calculate potential exposure or take of bottlenose dolphin for
each month. The weighting incorporated the number of piles that produce
the different zone sizes ensonified by each pile size/hammer/location.
The number of piles with each different zone size was multiplied by its
relevant ensonified area; those were then summed and the total was
divided by the total number of piles.
For example, if there are 5 piles with a 20 km\2\ Level B zone each
and 2 piles with a 50 km\2\ Level B zone, the formula would be:
((5 piles * 20 km\2\/pile) + (2 piles * 50 km\2\/pile))/(7 piles) =
weighted average of 28.6 km\2\.
The sum of potential exposures within the Core Monitoring Area
(daily sighting rate method) and outside the Core Monitoring Area
(density method for zones that extend into Chesapeake Bay) yields the
total number of potential bottlenose dolphin exposures (Table 26) for
each month and year.
BILLING CODE 3510-22-P
[[Page 1622]]
[GRAPHIC] [TIFF OMITTED] TP08JA21.007
BILLING CODE 3510-22-C
Level A harassment zones and areas are relatively small for
bottlenose dolphins. The largest Level A harassment isopleth is 236 m
for DTH pile installation of 60-inch steel pipe piles (casings) at the
South Trestle and covers an area less than 0.18 km\2\. Given the daily
sightings rates shown in Table 24, and the small Level A harassment
zones, HRCP and NMFS do not anticipate that bottlenose dolphins will
[[Page 1623]]
actually incur Level A harassment. However, because animals may enter
into a PTS zone before being sighted, HRCP has requested authorization
of Level A harassment for bottlenose dolphins as a precaution. Although
NMFS does not agree that a brief sighting of a marine mammal within a
Level A harassment zone calculated on the basis of accumulated energy
necessarily means that the animal has experienced Level A harassment,
we nevertheless propose to authorize take as requested by HRCP. HRCP
assumed that approximately 1 percent of the total harassment exposures
will be in the form of Level A harassment. HRCP has requested and NMFS
is proposing to authorize 124,045 exposures by Level B harassment and
1,257 exposures by Level A harassment of bottlenose dolphins divided
among the 5 project construction years (125,302 total exposures-1,257
Level A harassment takes = 124,045 Level B harassment takes). However,
due to the construction schedule, these takes will not occur equally
during each year of the LOA. Year 3 of the LOA is expected to have 306
takes by Level A harassment and 30,256 takes by Level B harassment for
a total of 30,562 proposed takes.
The total number of bottlenose dolphin takes by Level A and Level B
harassment is expected to be split between three bottlenose dolphin
stocks: Western North Atlantic Southern Migratory Coastal; Western
North Atlantic Northern Migratory Coastal; and NNCES. There is
insufficient data available to apportion the requested takes precisely
to each of these three stocks present in the project area. Given that
most of the NNCES stock are found in the Pamlico Sound Estuarine
System, the Project will assume that no more than 200 of the requested
takes will be from this stock during any given year. Since members of
the Western North Atlantic Northern Migratory Coastal and Western North
Atlantic Southern Migratory Coastal stocks are thought to occur in or
near the Project area in greater numbers, HRCP will conservatively
assume that no more than half of the remaining animals will belong to
either of these stocks. Additionally, a subset of these takes would
likely be comprised of Chesapeake Bay resident dolphins, although the
size of that population is unknown. It is assumed that an animal will
be taken once over a 24-hour period; however, the same individual may
be taken multiple times over the duration of the project. Therefore,
both the number of takes for each stock and the affected population
percentages represent the maximum potential take numbers.
Harbor Porpoise
Harbor porpoises are rarely seen in the project area although they
are known to occur in the coastal waters near Virginia Beach (Hayes et
al. 2020). They have been sighted on rare occasions in the Chesapeake
Bay closer to Norfolk. Density data does not exist for this species
within the project area. Sighting data collected by the U.S. Navy near
Naval Station Norfolk and Virginia Beach from 2012 to 2015 (Engelhaupt
et al. 2014, 2015, 2016) did not produce high enough sample sizes to
calculate densities. One group of two harbor porpoises was seen during
spring 2015 (Engelhaupt et al. 2016).
HRCP estimated that one group of two harbor porpoises could be
exposed to project-related underwater noise each month during the
spring (March-May) for a total of 6 harbor porpoises takes (i.e., 1
group of 2 individuals per month x 3 months per year = 6 harbor
porpoises) per year for Years 1-4, and 4 harbor porpoise takes in Year
5.
The largest calculated Level A harassment zone for harbor porpoises
extends 7,901 m from the noise source during DTH installation of 60-
inch steel pipe piles (casings) at the South Trestle, for a harassment
area of 102.16 km\2\ (Table 17). However, HRCP has proposed a 100-meter
shutdown zone for harbor porpoises. HRCP has requested small numbers of
take by Level A harassment for harbor porpoises during the project.
While NMFS does not agree that take by Level A harassment is likely,
due to the duration of time a harbor porpoise would be required to
remain within the Level A zone to accumulate enough energy to
experience PTS, we nevertheless propose to authorize limited take as
requested by HRCP. It is anticipated that 2 individuals may enter the
Level A harassment zone during pile installation and removal each
spring, for a total of 2 potential Level A harassment exposures per
year. Therefore, NMFS is proposing to authorize 4 takes by Level B
harassment each spring for Years 1-4 (6 total exposures-2 Level A
harassment takes = 4 Level B harassment takes). In Year 5, NMFS is
proposing to authorize 2 takes by Level B harassment and 2 by Level A
harassment.
Harbor Seal
HRCP estimated the expected number of harbor seals in the project
area using systematic, land- and vessel-based survey data for in-water
and hauled-out seals collected by the U.S. Navy at the CBBT rock armor
and portal islands from November 2014 through April 2019 (Rees et al.
2016; Jones et al. 2018; Jones and Rees 2020). The number of harbor
seals sighted by month from 2014 through 2019, in the Chesapeake Bay
waters, in the vicinity (lower Chesapeake Bay along the CBBT) of the
Project, ranged from 0 to 170 individuals Table 27. During the months
of June through October (Table 27 and Table 29) harbor seals are not
anticipated to be present in the Chesapeake Bay.
Table 27--Summary of Historical Harbor Seal Sightings by Month From 2014 to 2019
----------------------------------------------------------------------------------------------------------------
Monthly
Month 2014 2015 2016 2017 2018 2019 average
----------------------------------------------------------------------------------------------------------------
January............................. ........ ........ 33 120 170 7 82.5
February............................ ........ 39 80 106 159 21 81
March............................... ........ 55 61 41 0 18 43.8
April............................... ........ 10 1 3 3 4 4.2
May................................. ........ 3 0 0 0 ........ 0.8
--------------------------------------------------
June................................ Seals not expected to be present. ........ 0
July................................ Seals not expected to be present. ........ 0
August.............................. Seals not expected to be present. ........ 0
September........................... Seals not expected to be present. ........ 0
October............................. Seals not expected to be present. ........ 0
--------------------------------------------------
November............................ 1 0 1 0 3 ........ 1.3
[[Page 1624]]
December............................ 4 9 24 8 29 ........ 14.8
----------------------------------------------------------------------------------------------------------------
Table 28--Harbor Seal Survey Effort, Total Count, Max Count on a Single Survey Day, and the Average Number of
Seals Observed per Survey Day at the CBBT Survey Area
----------------------------------------------------------------------------------------------------------------
Number of Total seal Average daily Max daily seal
Field season survey days count seal count count
----------------------------------------------------------------------------------------------------------------
2014-2015....................................... 11 113 10 33
2015-2016....................................... 14 187 13 39
2016-2017....................................... 22 308 14 40
2017-2018....................................... 15 340 23 45
2018-2019....................................... 10 82 8 17
Average......................................... 14.4 186 13.6 34.8
----------------------------------------------------------------------------------------------------------------
Table 29--Summary of the Estimated Numbers of Harbor Seals Potentially Taken by Level A and Level B Harassment per Month per Year \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Annual
Year Nov Dec Jan Feb Mar Apr May Level A Level B total
--------------------------------------------------------------------------------------------------------------------------------------------------------
Year 1.................................................. 176.8 367.2 353.6 326.4 367.2 353.6 176.8 424 1,697 2,122
Year 2.................................................. 176.8 367.2 353.6 326.4 367.2 353.6 176.8 424 1,697 2,122
Year 3.................................................. 176.8 367.2 353.6 326.4 367.2 353.6 176.8 424 1,697 2,122
Year 4.................................................. 176.8 367.2 353.6 326.4 367.2 353.6 176.8 424 1,697 2,122
Year 5 *................................................ 176.8 367.2 353.6 326.4 367.2 0 0 318 1,273 1,591
Monthly 5-Year Total.................................... 884 1,836 1,768 1,632 1,836 1,414 707 2,015 8,062 10,077
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Harbor seals not expected June-October.
The estimated total number of harbor seals potentially exposed to
in-water noise at harassment levels is 13.6 per day (the average of the
5-year average daily harbor seal count) (Table 28) for 156 days based
on a 6-day work week from mid-November to mid-May. Seals are not
expected to be present in the Chesapeake Bay from June through October.
It is estimated that 13.6 harbor seals could be exposed per day to
Project-related underwater noise for 156 days for a total of 2,122
exposures per year for Years 1-4. In Year 5, it is estimated that 1,591
harbor seals could be exposed to Project-related underwater noise from
November through March (Table 29).
The largest Level A harassment isopleth associated with drilling
with a DTH hammer of 60-inch steel pipe piles (casings) at the South
Trestle for harbor seals is 3,550 meters (Table 17) with a Level A
harassment zone of 27.12 km\2\. It is possible that harbor seals could
enter this or other Level A harassment zones undetected. While NMFS
does not believe that take of harbor seals by Level A harassment is
likely due to accumulated energy that would be required to experience
injury, we nevertheless propose to authorize limited take as requested
by HRCP. It is anticipated that up to 20 percent of the total exposures
would be at or above the Level A harassment threshold. Therefore, HRCP
has requested and NMFS proposes to authorize 1,697 takes by Level B
harassment and 424 takes by Level A harassment for project years 1-4
and 1,273 Level B harassment takes and 318 Level A harassment takes of
harbor seals for project year 5 (Table 29).
Gray Seal
Gray seals are expected to be very uncommon in the Project area. As
described below, historical data indicate that approximately one gray
seal has been seen per year in the Chesapeake Bay. Similar to the
harbor seal, HRCP estimated the expected number of gray seals in the
Project area using systematic, land- and vessel-based survey data for
in-water and hauled-out seals collected by the U.S. Navy at the CBBT
rock armor and portal islands from 2014 through 2019 (Rees et al. 2016;
Jones et al. 2018; Jones and Rees 2020). Gray seals are not expected to
be present in the Chesapeake Bay during the months of March through
December. Between 2015 and 2019 only three individual seals were
observed, all in the month of February (i.e., 2015, 2016 and 2018).
As a precautionary measure, HRCP assumed that there could be three
gray seals taken by Level B harassment during each of the winter months
(December through February). Therefore, HRCP requested and NMFS is
proposing to authorize nine gray seal takes per year for years 1-4 (3
gray seals per month x 3 months per year = 9 gray seals) and 5 for
project year five for a total of 41 takes of gray seals (Table 30).
Given the size of the Level A harassment zones and potential for a gray
seal to be present within the zone for sufficient duration to incur
injury, nine takes by Level A harassment have also been requested (2
during years 1-4 and 1 during year 5). NMFS concurs with this
assessment and is proposing to authorize seven takes by Level B
harassment per year for years 1-4 (9 takes-2 takes by Level A
harassment = 7 takes by Level B harassment) and 4 takes for year 5 (5
total takes-1 take by Level A harassment = 4 takes by Level B
harassment). NMFS is also proposing to authorize 2 takes of gray seal
per year by Level A harassment for years 1-4 and a single take for year
5.
Table 30 below summarizes proposed take numbers by species per
project year while Table 31 describes the proposed authorized take for
all the species described above as a percentage of stock abundance.
[[Page 1625]]
Table 30--Estimated Take by Level A and Level B Harassment, by Species
--------------------------------------------------------------------------------------------------------------------------------------------------------
2021 2022 2023 2024 2025
Species -------------------------------------------------------------------------------------------------------------- Total
Level A Level B Level A Level B Level A Level B Level A Level B Level A Level B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale................. 2 35 2 35 2 35 2 35 0 24 172
Bottlenose dolphin............. 212 20,915 349 34,435 354 34,972 307 30,341 35 3,382 125,302
Harbor porpoise................ 2 4 2 4 2 4 2 4 2 2 30
Harbor seal.................... 424 1,697 424 1,697 424 1,697 424 1,697 318 1,273 10,075
Gray seal...................... 2 7 2 7 2 7 2 7 1 4 41
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 31--Maximum Annual Estimated Take by Level A and Level B Harassment, by Species and Stock in Comparison to
Stock Abundance
----------------------------------------------------------------------------------------------------------------
Level A Level B
Species Stock Stock harassment harassment Percent of
abundance take take stock
----------------------------------------------------------------------------------------------------------------
Humpback Whale................ Gulf of Maine... \b\ 12,312 2 35 0.3
Bottlenose Dolphin............ WNA Coastal, 6,639 175 17,386 264.5
Northern
Migratory \a\.
WNA Coastal, 3,751 175 17,386 468.2
Southern
Migratory \a\.
NNCES \c\....... 823 0 200 24.3
Harbor Porpoise............... Gulf of Maine/ 95,543 2 4 <0.01
Bay of Fundy.
Harbor Seal................... Western North 75,834 424 1,697 2.8
Atlantic.
Gray Seal..................... Western North 451,531 2 7 <0.01
Atlantic.
----------------------------------------------------------------------------------------------------------------
\a\ Take estimates are weighted based on calculated percentages of population for each distinct stock, assuming
animals present would follow same probability of presence in the project area. Please see the Small Numbers
section for additional information.
\b\ West Indies DPS.
\c\ Assumes multiple repeated takes of same individuals from small portion of each stock as well as repeated
takes of Chesapeake Bay resident population (size unknown). Please see the Small Numbers section for
additional information.
Proposed Mitigation
In order to issue an LOA under Section 101(a)(5)(A) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to such
activity, and other means of effecting the least practicable impact on
such species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of such species or stock for taking for certain
subsistence uses (latter not applicable for this action). NMFS
regulations require applicants for incidental take authorizations to
include information about the availability and feasibility (economic
and technological) of equipment, methods, and manner of conducting such
activity or other means of effecting the least practicable adverse
impact upon the affected species or stocks and their habitat (50 CFR
216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, we
carefully consider two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat.
This considers the nature of the potential adverse impact being
mitigated (likelihood, scope, range). It further considers the
likelihood that the measure will be effective if implemented
(probability of accomplishing the mitigating result if implemented as
planned) the likelihood of effective implementation (probability
implemented as planned); and
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost, impact on
operations, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
In addition to the measures described later in this section, HRCP
will employ the following mitigation measures:
For in-water heavy machinery work other than pile driving,
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;
HRCP will conduct briefings between construction
supervisors and crews and the marine mammal monitoring team prior to
the start of all pile driving activity and when new personnel join the
work, to explain responsibilities, communication procedures, marine
mammal monitoring protocol, and operational procedures;
For those marine mammals for which Level A or Level B
harassment take has not been requested, in-water pile installation/
removal will shut down immediately if such species are observed within
or entering the Level A or Level B harassment zone; and
If take reaches the authorized limit for an authorized
species, pile installation/removal will shut down immediately if these
species approach the Level A or Level B harassment zone to avoid
additional take.
The following mitigation measures apply to HRCP's in-water
construction activities.
Time Restriction
For pile driving, work would occur only during daylight hours, when
visual monitoring of marine mammals can be conducted. Installation or
removal of new piles will not commence after daylight hours.
Shutdown Zones
For all pile driving activities, HRCP will establish shutdown zones
for a marine mammal species which correspond to the Level A harassment
zones. The purpose of a shutdown zone is generally to define an area
within which shutdown of the activity would occur upon sighting of a
marine mammal (or in anticipation of an animal entering the defined
area). In some instances, however, large zone sizes will make it
impossible to monitor the entirety of the Level A harassment zones.
[[Page 1626]]
During use of a single hammer the following measures will be
employed by HRCP:
A minimum 10-meter shutdown zone will be implemented for
all species, pile sizes, and hammer types to prevent direct injury of
marine mammals.
A 15-meter shutdown zone will be implemented for seals to
prevent direct injury.
A 100-meter shutdown zone will be implemented for harbor
porpoises when utilizing a DTH hammer and impact hammering to prevent
direct injury.
When the Level A harassment zone is larger than 50 meters,
shutdown zones have been rounded up relative to the calculated Level A
harassment zones as a precautionary measure. HRCP will also document
the duration any animal spends within the Level A harassment zone.
When two or more vibratory hammers are in use HRCP will employ the
following measures:
A shutdown zone will be implemented for each species for
each vibratory hammer on days when it is anticipated that multiple
vibratory hammers will be used, whether at a single site or multiple
sites.
A 35-meter shutdown zone will be implemented for harbor
seals and gray seals to prevent direct injury.
An 85-meter shutdown zone will be implemented for harbor
porpoise to prevent direct injury.
A 55-meter shutdown zone will be implemented for humpback
whales to prevent direct injury.
Calculated Level A harassment zones and shutdown zones for each
activity and pile size and type are depicted in Table 32 and Table 33.
Note that shutdown zones in Table 33 include a 7 dB reduction due to
the use of bubble curtains. Compare shutdown zones in Table 32 with
Level A harassment zones contained in Tables 16, 17 and 18. Under some
pile driving scenarios, the Level A harassment zones are larger than
the specified shutdown zones.
Table 32--Shutdown Zones With No Attenuation for All Species
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment isopleth distance
Number of (meters)
Minutes (min) per pile or piles -----------------------------------------
Method Pile size and type strikes per pile installed or Cetaceans
removed per ------------------------------ Pinnipeds
day LF MF HF
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation and Removal.. 24-inch Pipe, Steel..... 15 min....................... 6 \1\10/55 10 \2\14/85 \3\15/35
15/55 21/85
30-inch Pipe, Steel, 30 min....................... 6 36/55 60/85
Concrete Filled.
36-inch Pipe, Steel..... 2.5 min...................... 8 10/55 13/85
2.5 min...................... 16 14/55 20/85
25 min....................... 1 10/55 15/85
2 16/55 23/85
3 20/55 30/85
30 min....................... 2 18/55 26/85
42-inch Pipe, Steel..... 15 min....................... 6 27/55 39/85
Sheet, Steel............ 15 min....................... 10 11/55 16/85
16-inch CCA, Timber..... 15 min....................... 4 10/55 12/85
Jetting............................. 42-inch Pipe, Steel..... 15 min....................... 1 10 10
Down-the-Hole Installation 30-inch Pipe, Steel, 36,000 strikes*.............. 6 1,950 70 100
Concrete Filled.
36-inch Pipe, Steel..... 2 940 34
60-inch Pipe, Steel..... 3 6,640 240
Impact Installation 24-inch Pipe, Steel..... 20 strikes................... 6 100 10
30-inch Pipe, Steel, 390 14
Concrete Filled.
36-inch Pipe, Steel..... 2 120 10
36-inch Pipe, Steel..... 3 160 10
24-inch Pipe, Concrete 1,050 strikes................ 1 80 10
Square.
54-inch Pipe, Concrete 420 15
Cylinder.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ A 55-meter shutdown zone will be implemented for humpback whales during concurrent vibratory driving of two or more hammers.
\2\ A 85-meter shutdown zone will be implemented for harbor porpoise during concurrent vibratory driving of two or more hammers.
\3\ A 35-meter shutdown zone will be implemented for harbor seals and gray seals during concurrent vibratory driving of two or more hammers.
Table 33--Shutdown Zones With Attenuation for All Species
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment isopleth distance (meters)
Number of ------------------------------------------------
Method Pile size and type Strikes per pile piles per Cetaceans Pinnipeds
day ------------------------------------------------
LF MF HF PW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Installation 24-inch Pipe, Steel...... 20 strikes............... 6 33 10 40 18
30-inch Pipe, Steel, 140 10 160 80
Concrete Filled.
36-inch Pipe, Steel...... 20 strikes............... 2 40 10 48 22
--------------------------------------------------------------------------------------------------------------------------------------------------------
Protected Species Observers
The placement of protected species observers (PSOs) during all pile
driving and removal activities (described in the Proposed Monitoring
and Reporting section) will ensure that the entire shutdown zone is
visible during pile driving and removal. Should environmental
conditions deteriorate such that marine mammals within the entire
shutdown zone would not be visible (e.g., fog, heavy rain), pile
driving and removal must be delayed until the PSO is confident marine
mammals within the shutdown zone could be detected. However, if work on
a pile has already begun, work is allowed to continue until that pile
is installed.
[[Page 1627]]
Establishment of Level A and Level B Harassment Zones
HRCP will establish monitoring zones based on calculated Level A
harassment isopleths associated with specific pile driving activities
and scenarios. These are areas beyond the established shutdown zones in
which animals could be exposed to sound levels that could result in
Level A harassment in the form of PTS. HRCP will also establish and
monitor Level B harassment zones which are areas where SPLs are equal
to or exceed the 160 dB rms threshold for impact driving and 120 dB rms
threshold during vibratory driving and DTH pile installation.
The Level A and Level B harassment monitoring zones are given in
Tables 16-19.
Monitoring for Level B Harassment
HRCP will monitor the Level B harassment zones to the extent
practicable, as well as Level A harassment zones extending beyond
shutdown zones. HRCP will monitor at least a portion of the Level B
harassment zone on all pile driving days. Monitoring zones provide
utility for observing by establishing monitoring protocols for areas
adjacent to the shutdown zones. Monitoring zones enable observers to be
aware of and communicate the presence of marine mammals in the project
area outside the shutdown zone and thus prepare for a potential
cessation of activity should the animal enter the shutdown zone.
Bubble Curtains
Use of air bubble curtain systems will be implemented by HRCP
during impact driving of steel piles except in situations where the
water depth is less than 20 ft in depth. The use of this sound
attenuation device will reduce SPLs and the size of the zones of
influence for Level A harassment and Level B harassment. Bubble
curtains will meet the following requirements:
The bubble curtain must distribute air bubbles around 100
percent of the piling perimeter for the full depth of the water column.
The lowest bubble ring shall be in contact with the
mudline and/or rock bottom for the full circumference of the ring, and
the weights attached to the bottom ring shall ensure 100 percent
mudline and/or rock bottom contact. No parts of the ring or other
objects shall prevent full mudline and/or rock bottom contact.
The bubble curtain shall be operated such that there is
proper (equal) balancing of air flow to all bubblers.
The applicant shall require that construction contractors
train personnel in the proper balancing of air flow to the bubblers and
corrections to the attenuation device to meet the performance
standards. This shall occur prior to the initiation of pile driving
activities.
Soft-Start
The use of soft-start procedures are believed to provide additional
protection to marine mammals by providing warning and/or giving marine
mammals a chance to leave the area prior to the hammer operating at
full capacity. For impact pile driving, HRCP will be required to
provide an initial set of strikes from the hammer at reduced energy,
with each strike followed by a 30-second waiting period. This procedure
will be conducted a total of three times before impact pile driving
begins. Soft start will 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. Soft start is not
required during vibratory or DTH pile driving activities.
If a marine mammal is present within the shutdown zone, ramping up
will be delayed until the PSO has determined, through sighting, that
the animal(s) has moved outside the shutdown zone. If a marine mammal
is present in the Level A or Level B harassment zone, ramping up may
begin and a Level A or Level B harassment take will be recorded. If a
marine mammal is present in the Level A or Level B harassment zone,
HRCP may elect to delay ramping up to avoid a Level A or Level B
harassment take. To avoid a take by Level A or Level B harassment,
ramping up will begin only after the PSO has determined, through
sighting, that the animal(s) has moved outside the corresponding Level
A or Level B harassment zone or 15 minutes have passed.
Pre-Activity Monitoring
Prior to the start of daily in-water construction activity, or
whenever a break in pile driving of 30 minutes or longer occurs, PSOs
will observe the shutdown and monitoring zones for a period of 30
minutes. The shutdown zone will be cleared when a marine mammal has not
been observed within the zone for that 30-minute period. If a marine
mammal is observed within the shutdown zone, a soft-start cannot
proceed until the animal has left the zone or has not been observed for
15 minutes. If the Level A and Level B harassment zones have been
observed for 30 minutes and non-permitted species are not present
within the zone, soft start procedures can commence and work can
continue even if visibility becomes impaired within the Level A or
Level B harassment monitoring zones. When a marine mammal permitted for
take by Level A or Level B harassment is present in the Level A or
Level B harassment zone, activities may begin and Level A or Level B
harassment take will be recorded as appropriate. If work ceases for
more than 30 minutes, the pre-activity monitoring of both the Level B
harassment and shutdown zone will commence again. Additionally, in-
water construction activity must be delayed or cease, if poor
environmental conditions restrict full visibility of the shut-down
zone(s) until the entire shut-down zone(s) is visible.
Based on our evaluation of HRCP's proposed measures, as well as
other measures considered by NMFS, NMFS has preliminarily determined
that the proposed mitigation measures provide the means of effecting
the least practicable impact on the affected species or stocks and
their habitat, paying particular attention to rookeries, mating
grounds, and areas of similar significance.
Proposed Monitoring and Reporting
In order to issue an LOA for an activity, section 101(a)(5)(A) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. NMFS' MMPA implementing
regulations further describe the information that an applicant should
provide when requesting an authorization (50 CFR 216.104 (a)(13)),
including the means of accomplishing the necessary monitoring and
reporting that will result in increased knowledge of the species and
the level of taking or impacts on populations of marine mammals.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density).
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas).
[[Page 1628]]
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors.
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks.
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat).
Mitigation and monitoring effectiveness.
HRCP will submit a Marine Mammal Monitoring Plan which must be
approved by NMFS in advance of the start of construction.
Visual Monitoring
Marine mammal monitoring during pile driving and removal must be
conducted by PSOs in a manner consistent with the following:
Independent PSOs (i.e., not construction personnel) who
have no other assigned tasks during monitoring periods must be used;
At least one PSO must have prior experience performing the
duties of a PSO during construction activity pursuant to a NMFS-issued
incidental take authorization;
Other PSOs may substitute education (degree in biological
science or related field) or training for experience;
Where a team of three or more PSOs is required, a lead
observer or monitoring coordinator must be designated. The lead
observer must have prior experience working as a marine mammal observer
during construction; and
HRCP must submit PSO Curriculum Vitae for approval by NMFS
prior to the onset of pile driving.
PSOs must have the following additional qualifications:
Ability to conduct field observations and collect data
according to assigned protocols;
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, times, and reason for implementation
of mitigation (or why mitigation was not implemented when required);
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.
PSOs will be positioned at the best practical vantage point(s). The
position(s) may vary based on construction activity and location of
piles or equipment. At least one of the monitoring locations will have
an unobstructed view of the pile being driven, and an unobstructed view
of the Level A shutdown and Level B harassment zones, Core Monitoring
Area, as well as the 100-meter shutdown zone.
Between one and four PSOs will be stationed at locations offering
the best available views of the Level A and Level B harassment
monitoring zones during in-water pile installation and removal,
depending on where active in-water work is taking place. It is
anticipated that a PSO will observe from the North Island when in-water
pile installation is occurring at the North Island and North Trestle.
If the view field is adequate, Level A and Level B harassment zones may
be monitored for multiple pile driving locations by the same individual
PSO. Two PSOs will be located at the South Island, where they will
monitor for marine mammals passing into and out of the Core Monitoring
Area as well as monitor the active hammer sites. This location also
provides good views to the east for monitoring when zones extend beyond
the Core Monitoring Area into Chesapeake Bay. One PSO will be stationed
on Willoughby Spit or a similar location that offers the best available
views of the Level A and Level B harassment monitoring zones during in-
water pile installation and removal within Willoughby Bay. Finally, on
days when use of multiple hammers is planned and it is anticipated that
the Level B harassment isopleth will encompass the CBBT, a PSO will be
located on one of the CBBT Portal Islands to monitor the extended
ensonified area. A central position will generally be staffed by the
lead PSO, who will monitor the shutdown zones and communicate with
construction personnel about shutdowns and take management. PSOs at the
pile installation and removal locations will be able to see at least a
radius around the construction site that exceeds the largest Level A
harassment zone. PSOs will watch for marine mammals entering and
leaving the James River and will alert the lead PSO of the number and
species sighted, so that no unexpected marine mammals will approach the
construction site. This will minimize Level A harassment take of all
species.
Decibel addition is not a consideration when sound fields do not
overlap at the sound sources. Willoughby Bay is largely surrounded by
land, and sound will be prevented from propagating to other Project
construction sites. Therefore, Willoughby Bay will be treated as an
independent site with its own monitoring and shutdown zones, as well as
observer requirements when construction is taking place within the bay.
The Bay is relatively small and will be monitored from the construction
site by one to two observers.
Reporting
HRCP would submit an annual draft report for each construction year
to NMFS within 90 calendar days of the completion of marine mammal
monitoring. A final annual report will be prepared and submitted to
NMFS within 30 days following receipt of comments on the draft report
from NMFS.
The report will detail the monitoring protocol and summarize the
data recorded during monitoring. Specifically, the report must include
Dates and times (begin and end) of all marine mammal
monitoring.
Construction activities occurring during each daily
observation period, including how many and what type of piles were
driven or removed and by what method (i.e., impact or vibratory).
Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance (if less
than the harassment zone distance).
The number of marine mammals observed, by species,
relative to the pile location and if pile driving or removal was
occurring at time of sighting.
Age and sex class, if possible, of all marine mammals
observed.
PSO locations during marine mammal monitoring.
Distances and bearings of each marine mammal observed to
the pile being driven or removed for each sighting (if pile driving or
removal was occurring at time of sighting).
Description of any marine mammal behavior patterns during
observation, including direction of travel and
[[Page 1629]]
estimated time spent within the Level A and Level B harassment zones
while the source was active.
Number of marine mammals detected within the harassment
zones, by species.
Detailed information about any implementation of any
mitigation triggered (e.g., shutdowns and delays), a description of
specific actions that ensued, and resulting behavior of the animal, if
any.
Description of attempts to distinguish between the number
of individual animals taken and the number of incidences of take, such
as ability to track groups or individuals.
If no comments are received from NMFS within 30 days, the draft
report will constitute the final report. If comments are received, a
final report addressing NMFS comments must be submitted within 30 days
after receipt of comments.
In the event that personnel involved in the construction activities
discover an injured or dead marine mammal, HRCP shall report the
incident to the Office of Protected Resources (OPR) (301-427-8401),
NMFS and to the Greater Atlantic Region New England/Mid-Atlantic
Regional Stranding Coordinator as soon as feasible. If the death or
injury was clearly caused by the specified activity, HRCP must
immediately cease the specified activities until NMFS is able to review
the circumstances of the incident and determine what, if any,
additional measures are appropriate to ensure compliance with the terms
of the authorization. HRCP must not resume their activities until
notified by NMFS.
The report must include the following information:
i. Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
ii. Species identification (if known) or description of the
animal(s) involved;
iii. Condition of the animal(s) (including carcass condition if the
animal is dead);
iv. Observed behaviors of the animal(s), if alive;
v. If available, photographs or video footage of the animal(s); and
vi. General circumstances under which the animal was discovered.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact 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 (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any responses (e.g., intensity, duration), the context
of any responses (e.g., critical reproductive time or location,
migration), as well as effects on habitat, and the likely effectiveness
of the mitigation. We also assess the number, intensity, and context of
estimated takes by evaluating this information relative to population
status. Consistent with the 1989 preamble for NMFS's implementing
regulations (54 FR 40338; September 29, 1989), the impacts from other
past and ongoing anthropogenic activities are incorporated into this
analysis via their impacts on the environmental baseline (e.g., as
reflected in the regulatory status of the species, population size and
growth rate where known, ongoing sources of human-caused mortality, or
ambient noise levels).
To avoid repetition, this introductory discussion of our analyses
applies to all of the species listed in Table 31, given that many of
the anticipated effects of this project on different marine mammal
stocks are expected to be relatively similar in nature. Where there are
meaningful differences between species or stocks in anticipated
individual responses to activities, impact of expected take on the
population due to differences in population status, or impacts on
habitat, they are described independently in the analysis below.
Pile driving activities associated with the 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 from underwater sounds generated by pile driving.
Potential takes could occur if marine mammals are present in zones
ensonified above the thresholds for Level B harassment, identified
above, while activities are underway. No serious injury or mortality
would be expected even in the absence of the proposed mitigation
measures.
A limited number of animals could experience Level A harassment in
the form of PTS if they remain within the Level A harassment zone long
enough during certain impact driving scenarios. However, the number of
animal affected and the degree of injury is expected to be limited to,
at most, mild PTS. Furthermore, the reproduction or survival of the
individual animals is not likely to affected. It is expected that, if
hearing impairments occurs, most likely the affected animal would lose
a few dB in its hearing sensitivity, which in most cases is not likely
to affect its survival and recruitment.
HRCP's proposed pile driving activities and associated impacts will
occur within a limited portion of the confluence of the Chesapeake Bay
area. Localized noise exposures produced by project activities may
cause short-term behavioral modifications in affected cetaceans and
pinnipeds. However, as described previously, the mitigation and
monitoring measures are expected to further reduce the likelihood of
injury as well as reduce behavioral disturbances.
Effects on individuals that are taken by Level B harassment, on the
basis of reports in the literature as well as monitoring from other
similar activities, will likely be limited to reactions such as
increased swimming speeds, increased surfacing time, or decreased
foraging (if such activity were occurring) (e.g., Thorson and Reyff
2006). Individual animals, even if taken multiple times, will most
likely 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. The
pile driving activities analyzed here are similar to, or less impactful
than, numerous other construction activities conducted along the
Atlantic coast, which have taken place with no known long-term adverse
consequences from behavioral harassment. Furthermore, many projects
similar to this one are also believed to result in multiple takes of
individual animals without any documented long-term adverse effects.
Level B harassment will be minimized through use of mitigation measures
described herein and, if sound produced by project activities is
sufficiently disturbing, animals are likely to simply avoid the area
while the activity is occurring, particularly as the project is located
on a busy waterfront with high amounts of vessel traffic.
As previously described, UMEs have been declared for Northeast
pinnipeds (including harbor seal and gray seal) and Atlantic humpback
whales. However, we do not expect takes proposed for authorization in
this action to exacerbate or compound upon these ongoing UMEs. As noted
previously, no injury, serious injury, or mortality is expect or
proposed for authorization,
[[Page 1630]]
and Level A and Level B harassment takes of humpback whale, harbor seal
and gray seal will be reduced to the level of least practicable adverse
impact through the incorporation of the proposed mitigation measures.
For the WNA stock of gray seal, the estimated stock abundance is
451,431 animals, including the Canadian portion of the stock (estimated
27,131 animals in the U.S. portion of the stock). Given that only 7
takes by Level B harassment and two takes by Level A harassment are
proposed for this stock annually, we do not expect this proposed
authorization to exacerbate or compound upon the ongoing UME.
With regard to humpback whales, the UME does not yet provide cause
for concern regarding population-level impacts. Despite the UME, the
relevant population of humpback whales (the West Indies breeding
population, or distinct population segment (DPS)) remains healthy.
Prior to 2016, humpback whales were listed under the ESA as an
endangered species worldwide. Following a 2015 global status review
(Bettridge et al., 2015), NMFS established 14 DPSs with different
listing statuses (81 FR 62259; September 8, 2016) pursuant to the ESA.
The West Indies DPS, which consists of the whales whose breeding range
includes the Atlantic margin of the Antilles from Cuba to northern
Venezuela, and whose feeding range primarily includes the Gulf of
Maine, eastern Canada, and western Greenland, was delisted. The status
review identified harmful algal blooms, vessel collisions, and fishing
gear entanglements as relevant threats for this DPS, but noted that all
other threats are considered likely to have no or minor impact on
population size or the growth rate of this DPS (Bettridge et al.,
2015). As described in Bettridge et al. (2015), the West Indies DPS has
a substantial population size (i.e., 12,312 (95 percent CI 8,688-
15,954) whales in 2004-05 (Bettridge et al. 2003)), and appears to be
experiencing consistent growth. Further, NMFS is proposing to authorize
no more than 35 takes by Level B harassment annually of humpback whale.
For the WNA stock of harbor seals, the estimated abundance is
75,834 individuals. The estimated M/SI for this stock (350) is well
below the PBR (2,006). As such, the proposed Level B harassment takes
of harbor seal are not expected to exacerbate or compound upon the
ongoing UMEs.
The project is also not expected to have significant adverse
effects on affected marine mammals' habitats. The project activities
will not modify existing marine mammal habitat for a significant amount
of time. The activities may cause some fish to leave the area of
disturbance, thus temporarily impacting marine mammals' foraging
opportunities in a limited portion of the foraging range; but, because
of the relatively small area of the habitat that may be affected (with
no known particular importance to marine mammals), the impacts to
marine mammal habitat are not expected to cause significant or long-
term negative consequences. Furthermore, there are no known
biologically important areas (BIAs), ESA-designated critical habitat,
rookeries, or features of special significance for foraging or
reproduction.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect the species or stock
through effects on annual rates of recruitment or survival:
No serious injury or mortality is anticipated or
authorized;
Authorized Level A harassment would be limited and of low
degree;
The intensity of anticipated takes by Level B harassment
is relatively low for all stocks;
The number of anticipated takes is very low for humpback
whale, harbor porpoise, and gray seal;
The specified activity and associated ensonifed areas are
very small relative to the overall habitat ranges of all species and do
not include habitat areas of special significance;
The lack of anticipated significant or long-term negative
effects to marine mammal habitat; and
The presumed efficacy of the mitigation measures in
reducing the effects of the specified activity.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity will have a negligible impact on
all affected marine mammal species or stocks.
Small Numbers
As noted above, only small numbers of incidental take may be
authorized under section 101(a)(5)(A) of the MMPA for specified
activities other than military readiness activities. The MMPA does not
define small numbers and so, in practice, where estimated numbers are
available, NMFS compares the number of individuals taken to the most
appropriate estimation of abundance of the relevant species or stock in
our determination of whether an authorization is limited to small
numbers of marine mammals. When the predicted number of individuals to
be taken is fewer than one third of the species or stock abundance, the
take is considered to be of small numbers. Additionally, other
qualitative factors may be considered in the analysis, such as the
temporal or spatial scale of the activities.
The maximum annual take of take of humpback whale, harbor porpoise,
harbor seal, and gray seal comprises less than one-third of the best
available stock abundance estimate for each of these stocks (Table 31).
The maximum number of animals authorized to be taken from these stocks
would be considered small relative to the relevant stock's abundances
even if each estimated taking occurred to a new individual, which is an
unlikely scenario.
Three bottlenose dolphin stocks could occur in the project area:
WNA Coastal Northern Migratory, WNA Coastal Southern Migratory, and
NNCES stocks. Therefore, the estimated takes of bottlenose dolphin by
Level B harassment would likely be portioned among these stocks. Based
on the stocks' respective occurrence in the area, NMFS estimated that
there would be no more than 200 takes from the NNCES stock each year
over the five-year period, with the remaining takes evenly split
between the northern and southern migratory coastal stocks. Based on
consideration of various factors described below, we have determined
the maximum number of individuals taken per year would likely comprise
less than one-third of the best available population abundance estimate
of either coastal migratory stock.
Both the WNA Coastal Northern Migratory and WNA Coastal Southern
Migratory stocks have expansive ranges and they are the only dolphin
stocks thought to make broad-scale, seasonal migrations in coastal
waters of the western North Atlantic. Given the large ranges associated
with these stocks it is unlikely that large segments of either stock
would approach the project area and enter into the Chesapeake Bay. The
majority of both stocks are likely to be found widely dispersed across
their respective habitat ranges and unlikely to be concentrated in or
near the Chesapeake Bay.
Furthermore, the Chesapeake Bay and nearby offshore waters
represent the boundaries of the ranges of each of the two coastal
stocks during migration. The WNA Coastal Northern Migratory stock
[[Page 1631]]
occurs during warm water months from coastal Virginia, including the
Chesapeake Bay to Long Island, New York. The stock migrates south in
late summer and fall. During cold-water months, dolphins may occur in
coastal waters from Cape Lookout, North Carolina, to the North
Carolina/Virginia border. During January-March, the WNA Coastal
Southern Migratory stock appears to move as far south as northern
Florida. From April to June, the stock moves back north to North
Carolina. During the warm water months of July-August, the stock is
presumed to occupy coastal waters north of Cape Lookout, North
Carolina, to Assateague, Virginia, including the Chesapeake Bay. There
is likely some overlap between the northern and southern migratory
stocks during spring and fall migrations, but the extent of overlap is
unknown.
The Chesapeake Bay and waters offshore of its mouth are located on
the periphery of the migratory ranges of both coastal stocks (although
during different seasons). Additionally, each of the migratory coastal
stocks are likely to be located in the vicinity of the Chesapeake Bay
for relatively short timeframes. Given the limited number of animals
from each migratory coastal stock likely to be found at the seasonal
migratory boundaries of their respective ranges, in combination with
the short time periods (~two months) animals might remain at these
boundaries, it is reasonable to assume that takes are likely to occur
to only a small portion of either of the migratory coastal stocks.
Both migratory coastal stocks likely overlap with the NNCES stock
at various times during their seasonal migrations. The NNCES stock is
defined as animals that primarily occupy waters of the Pamlico Sound
estuarine system (which also includes Core, Roanoke, and Albemarle
sounds, and the Neuse River) during warm water months (July-August).
Animals from this stock also use coastal waters (<=1 km from shore) of
North Carolina from Beaufort north to Virginia Beach, Virginia,
including the lower Chesapeake Bay. Comparison of dolphin photo-
identification data confirmed that limited numbers of individual
dolphins observed in Roanoke Sound have also been sighted in the
Chesapeake Bay (Young, 2018). Like the migratory coastal dolphin
stocks, the NNCES stock covers a large range. The spatial extent of
most small and resident bottlenose dolphin populations is on the order
of 500 km\2\, while the NNCES stock occupies over 8,000 km\2\
(LeBrecque et al., 2015). Given this large range, it is again unlikely
that a preponderance of animals from the NNCES stock would depart the
North Carolina estuarine system and travel to the northern extent of
the stock's range. However, recent evidence suggests that there is
likely a small resident community of NNCES dolphins of indeterminate
size that inhabits the Chesapeake Bay year-round (E. Patterson, NMFS,
pers. comm.).
Many of the dolphin observations in the Bay are likely repeated
sightings of the same individuals. The Potomac-Chesapeake Dolphin
Project has observed over 1,200 unique animals since observations began
in 2015. Re-sightings of the same individual can be highly variable.
Some dolphins are observed once per year, while others are highly
regular with greater than 10 sightings per year (J. Mann, Potomac-
Chesapeake Dolphin Project, pers. comm.). Similarly, using available
photo-identification data, Engelhaupt et al. (2016) determined that
specific individuals were often observed in close proximity to their
original sighting locations and were observed multiple times in the
same season or same year. Ninety-one percent of re-sighted individuals
(100 of 110) in the study area were recorded less than 30 km from the
initial sighting location. Multiple sightings of the same individual
would considerably reduce the number of individual animals that are
taken by Level B harassment. Furthermore, the existence of a resident
dolphin population in the Bay would increase the percentage of dolphin
takes that are actually re-sightings of the same individuals in any
given year.
In summary and as described above, the following factors primarily
support our determination regarding the incidental take of small
numbers of the affected stocks of bottlenose dolphin:
Potential bottlenose dolphin takes in the project area are
likely to be allocated among three distinct stocks;
Bottlenose dolphin stocks in the project area have
extensive ranges and it would be unlikely to find a high percentage of
any one stock concentrated in a relatively small area such as the
project area or the Chesapeake Bay;
The Chesapeake Bay represents the migratory boundary for
each of the specified dolphin stocks and it would be unlikely to find a
high percentage of any stock concentrated at such boundaries; and
Many of the takes would likely be repeats of the same
animals and likely from a resident population of the Chesapeake Bay.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals will be taken relative to the population size
of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
determined that the total taking of affected species or stocks would
not have an unmitigable adverse impact on the availability of such
species or stocks for taking for subsistence purposes.
Adaptive Management
The regulations governing the take of marine mammals incidental to
HRCP construction activities would contain an adaptive management
component. The reporting requirements associated with this proposed
rule are designed to provide NMFS with monitoring data from completed
projects to allow consideration of whether any changes are appropriate.
The use of adaptive management allows NMFS to consider new information
from different sources to determine (with input from HRCP regarding
practicability) on an annual or biennial basis if mitigation or
monitoring measures should be modified (including additions or
deletions). Mitigation measures could be modified if new data suggests
that such modifications would have a reasonable likelihood of reducing
adverse effects to marine mammals and if the measures are practicable.
The following are some of the possible sources of applicable data
to be considered through the adaptive management process: (1) Results
from monitoring reports, as required by MMPA authorizations; (2)
results from general marine mammal and sound research; and (3) any
information which reveals that marine mammals may have been taken in a
manner, extent, or number not authorized by these regulations or
subsequent LOAs.
Endangered Species Act
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of
incidental take authorizations, NMFS consults internally whenever we
[[Page 1632]]
propose to authorize take for endangered or threatened species.
No incidental take of ESA-listed species is proposed for
authorization or expected to result from this activity. Therefore, NMFS
has determined that formal consultation under section 7 of the ESA is
not required for this action.
Request for Information
NMFS requests interested persons to submit comments, information,
and suggestions concerning HRCP's request and the proposed regulations
(see ADDRESSES). All comments will be reviewed and evaluated as we
prepare a final rule and make final determinations on whether to issue
the requested authorization. This notice and referenced documents
provide all environmental information relating to our proposed action
for public review.
Classification
Pursuant to the procedures established to implement Executive Order
12866, the Office of Management and Budget has determined that this
proposed rule is not significant. Pursuant to section 605(b) of the
Regulatory Flexibility Act (RFA), the Chief Counsel for Regulation of
the Department of Commerce has certified to the Chief Counsel for
Advocacy of the Small Business Administration that this proposed rule,
if adopted, would not have a significant economic impact on a
substantial number of small entities. HRCP is the sole entity that
would be subject to the requirements in these proposed regulations, and
HRCP is not a small governmental jurisdiction, small organization, or
small business, as defined by the RFA. Because of this certification, a
regulatory flexibility analysis is not required and none has been
prepared.
Notwithstanding any other provision of law, no person is required
to respond to nor shall a person be subject to a penalty for failure to
comply with a collection of information subject to the requirements of
the Paperwork Reduction Act (PRA) unless that collection of information
displays a currently valid OMB control number. This proposed rule
contains collection-of-information requirements subject to the
provisions of the PRA. These requirements have been approved by OMB
under control number 0648-0151 and include applications for
regulations, subsequent LOAs, and reports.
List of Subjects in 50 CFR Part 217
Administrative practice and procedure, Alaska, Endangered and
threatened species, Exports, Fish, Imports, Indians, Labeling, Marine
mammals, Oil and gas exploration, Penalties, Reporting and
recordkeeping requirements, Seafood, Transportation, Wildlife.
Dated: December 29, 2020.
Samuel D. Rauch, III,
Deputy Assistant Administrator for Regulatory Programs, National Marine
Fisheries Service.
For reasons set forth in the preamble, 50 CFR part 217 is proposed
to be amended as follows:
PART 217--REGULATIONS GOVERNING THE TAKING AND IMPORTING OF MARINE
MAMMALS
0
1. The authority citation for part 217 continues to read as follows:
Authority: 16 U.S.C. 1361 et seq., unless otherwise noted.
0
2. Add subpart W to read as follows:
Subpart W--Taking and Importing Marine Mammals Incidental to Hampton
Roads Connector Partners Construction at Norfolk, Virginia
Sec.
217.20 Specified activity and geographical region.
217.21 Effective dates.
217.22 Permissible methods of taking.
217.23 Prohibitions.
217.24 Mitigation requirements.
217.25 Requirements for monitoring and reporting.
217.26 Letters of Authorization.
217.27 Renewals and modifications of Letters of Authorization.
217.28-217.29 [Reserved]
Subpart W--Taking and Importing Marine Mammals Incidental to
Hampton Roads Connector Partners Construction at Norfolk, Virginia
Sec. 217.20 Specified activity and geographical region.
(a) Regulations in this subpart apply only to the Hampton Roads
Connector Partners (HRCP) and those persons it authorizes or funds to
conduct activities on its behalf for the taking of marine mammals that
occurs in the areas outlined in paragraph (b) of this section and that
occurs incidental to construction activities including marine structure
maintenance, pile replacement, and select waterfront improvements at
the Hampton Roads Bridge Tunnel Expansion Project (HRBT).
(b) The taking of marine mammals by HRCP may be authorized in a
Letter of Authorization (LOA) only if it occurs at the Hampton Roads
Bridge Tunnel Expansion project location.
Sec. 217.21 Effective dates.
Regulations in this subpart are effective from [EFFECTIVE DATE OF
THE FINAL RULE] to [DATE 5 YEARS AFTER EFFECTIVE DATE OF THE FINAL
RULE].
Sec. 217.22 Permissible methods of taking.
(a) Under an LOA issued pursuant to Sec. Sec. 216.106 of this
chapter and 217.26, the Holder of the LOA (hereinafter ``HRCP'') may
incidentally, but not intentionally, take marine mammals within the
area described in Sec. 217.20(b) by Level A and Level B harassment
associated with construction activities, provided the activity is in
compliance with all terms, conditions, and requirements of the
regulations in this subpart and the applicable LOA.
(b) [Reserved]
Sec. 217.23 Prohibitions.
(a) Except for the takings contemplated in Sec. 217.22 and
authorized by an LOA issued under Sec. Sec. 216.106 of this chapter
and 217.26, it is unlawful for any person to do any of the following in
connection with the activities described in Sec. 217.20:
(1) Violate, or fail to comply with, the terms, conditions, and
requirements of this subpart or a LOA issued under Sec. Sec. 216.106
of this chapter and 217.26;
(2) Take any marine mammal not specified in such LOA;
(3) Take any marine mammal specified in such LOA in any manner
other than as specified;
(4) Take a marine mammal specified in such LOA if NMFS determines
such taking results in more than a negligible impact on the species or
stocks of such marine mammal; or
(5) Take a marine mammal specified in such LOA if NMFS determines
such taking results in an unmitigable adverse impact on the species or
stock of such marine mammal for taking for subsistence uses.
(b) [Reserved]
Sec. 217.24 Mitigation requirements.
(a) When conducting the activities identified in Sec. 217.20(a),
the mitigation measures contained in any LOA issued under Sec. Sec.
216.106 of this chapter and 217.26 must be implemented. These
mitigation measures shall include but are not limited to:
(1) A copy of any issued LOA must be in the possession of HRCP, its
designees, and work crew personnel operating under the authority of the
issued LOA.
(2) HRCP shall conduct briefings for construction supervisors and
crews, the monitoring team, and HRCP staff prior to the start of all
pile driving activity, and when new personnel join the work, in order
to explain responsibilities, communication procedures, the marine
[[Page 1633]]
mammal monitoring protocol, and operational procedures.
(3) For in-water heavy machinery work other than pile driving, if a
marine mammal comes within 10 meters (m), HRCP shall cease operations
and reduce vessel speed to the minimum level required to maintain
steerage and safe working conditions.
(4) For all pile driving activity, HRCP shall implement a minimum
shutdown zone of a 10 m radius around the pile. If a marine mammal
comes within or approaches the shutdown zone, such operations shall
cease.
(5) For all pile driving activity, HRCP shall implement shutdown
zones with radial distances as identified in a LOA issued under
Sec. Sec. 216.106 of this chapter and 217.26. If a marine mammal comes
within or approaches the shutdown zone, such operations shall cease.
(6) HRCP deploy protected species observers (observers or PSOs) as
indicated in its Marine Mammal Monitoring Plan approved by NMFS.
(7) For all pile driving activities, between one and four observers
shall be stationed at the best vantage points practicable to monitor
for marine mammals and implement shutdown/delay procedures.
(8) Monitoring shall take place from 30 minutes prior to initiation
of pile driving activity through 30 minutes post-completion of pile
driving activity. Pre-activity monitoring shall be conducted for 30
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. If a marine mammal is observed within the shutdown zone, a
soft-start cannot proceed until the animal has left the zone or has not
been observed for 15 minutes. Monitoring shall occur throughout the
time required to drive a pile. If in-water pile installation and
removal work ceases for more than 30 minutes, the pre-activity
monitoring of the shutdown zones must commence. A determination that
the shutdown zone is clear must be made during a period of good
visibility (i.e., the entire shutdown zone and surrounding waters must
be visible to the naked eye).
(9) If a marine mammal approaches or enters the shutdown zone, all
pile driving activities at that location shall be halted. In the event
of a delay, the activity may not commence or resume 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.
(10) Pile driving activity must be halted upon observation of
either a species for which incidental take is not authorized or a
species for which incidental take has been authorized but the
authorized number of takes has been met, entering or within the
harassment zone.
(11) Should environmental conditions deteriorate such that marine
mammals within the entire shutdown zone would not be visible (e.g.,
fog, heavy rain), HRCP shall delay pile driving and removal until
observers are confident marine mammals within the shutdown zone could
be detected.
(12) Monitoring shall be conducted by trained observers, who shall
have no other assigned tasks during monitoring periods. Trained
observers shall be placed at 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. HRCP
shall adhere to the following additional observer qualifications:
(i) Independent observers are required;
(ii) At least one observer must have prior experience working as an
observer;
(iii) Other observers may substitute education (degree in
biological science or related field) or training for experience;
(iv) Where a team of three or more observers are required, one
observer shall be designated as lead observer or monitoring
coordinator. The lead observer must have prior experience working as an
observer; and
(v) HRCP must submit PSO CVs for approval by NMFS prior to the
beginning of pile driving and drilling.
(13) HRCP shall use soft start techniques for impact pile driving.
Soft start for impact driving requires HRCP and those persons it
authorizes to provide an initial set of three strikes at reduced
energy, followed by a thirty-second waiting period, then two subsequent
reduced energy three-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 thirty minutes or
longer.
(14) HRCP shall employ bubble curtain systems during impact driving
of steel piles except under conditions where the water depth is less
than 20 feet in depth. Bubble curtains must meet the following
requirements:
(i) The bubble curtain must distribute air bubbles around 100
percent of the piling perimeter for the full depth of the water column.
(ii) The lowest bubble ring must be in contact with the mudline
and/or rock bottom for the full circumference of the ring, and the
weights attached to the bottom ring shall ensure 100 percent mudline
and/or rock bottom contact. No parts of the ring or other objects shall
prevent full mudline and/or rock bottom contact.
(iii) The bubble curtain must be operated such that there is proper
(equal) balancing of air flow to all bubblers.
(iv) HRCP shall require that construction contractors train
personnel in the proper balancing of air flow to the bubblers and
corrections to the attenuation device to meet the performance
standards. This shall occur prior to the initiation of pile driving
activities.
(b) [Reserved]
Sec. 217.25 Requirements for monitoring and reporting.
(a) HRCP shall submit a Marine Mammal Monitoring Plan to NMFS for
approval in advance of construction.
(b) HRCP shall deploy observers as indicated in its approved Marine
Mammal Monitoring Plan.
(c) Observers shall be trained in marine mammal identification and
behaviors. Observers shall have no other construction-related tasks
while conducting monitoring.
(d) HRCP shall monitor the Level B harassment zones and Level A
harassment zones extending beyond the designated shutdown zones to the
extent practicable.
(e) HRCP shall monitor the shutdown zones during all pile driving
and removal activities.
(f) HRCP shall submit a draft annual monitoring report to NMFS
within 90 work days of the completion of annual marine mammal
monitoring. The report must detail the monitoring protocol and
summarize the data recorded during monitoring. If no comments are
received from NMFS within 30 days, the draft report will constitute the
final report. If comments are received, a final report addressing NMFS
comments must be submitted within 30 days after receipt of comments.
Specifically, the report must include:
(1) Dates and times (begin and end) of all marine mammal
monitoring.
(2) Construction activities occurring during each daily observation
period, including how many and what type of piles were driven or
removed and by what method (i.e., impact or vibratory).
[[Page 1634]]
(3) Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance (if less
than the harassment zone distance).
(4) The number of marine mammals observed, by species, relative to
the pile location and if pile driving or removal was occurring at time
of sighting.
(5) Age and sex class, if possible, of all marine mammals observed.
(6) PSO locations during marine mammal monitoring.
(7) Distances and bearings of each marine mammal observed to the
pile being driven or removed for each sighting (if pile driving or
removal was occurring at time of sighting).
(8) Description of any marine mammal behavior patterns during
observation, including direction of travel and estimated time spent
within the Level A and Level B harassment zones while the source was
active.
(9) Number of marine mammals detected within the harassment zones,
by species.
(10) Detailed information about any implementation of any
mitigation triggered (e.g., shutdowns and delays), a description of
specific actions that ensued, and resulting behavior of the animal, if
any.
(11) Description of attempts to distinguish between the number of
individual animals taken and the number of incidences of take, such as
ability to track groups or individuals.
(g) In the event that personnel involved in the construction
activities discover an injured or dead marine mammal, HRCP shall report
the incident to the Office of Protected Resources (OPR) (301-427-8401),
NMFS and to the Greater Atlantic Region New England/Mid-Atlantic
Regional Stranding Coordinator as soon as feasible. If the death or
injury was clearly caused by the specified activity, HRCP must
immediately cease the specified activities until NMFS is able to review
the circumstances of the incident and determine what, if any,
additional measures are appropriate to ensure compliance with the terms
of the authorization. HRCP must not resume their activities until
notified by NMFS. The report must include the following information:
(1) Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
(2) Species identification (if known) or description of the
animal(s) involved;
(3) Condition of the animal(s) (including carcass condition if the
animal is dead);
(4) Observed behaviors of the animal(s), if alive;
(5) If available, photographs or video footage of the animal(s);
and
(6) General circumstances under which the animal was discovered.
Sec. 217.26 Letters of Authorization.
(a) To incidentally take marine mammals pursuant to the regulations
in this subpart, HRCP must apply for and obtain an LOA.
(b) An LOA, unless suspended or revoked, may be effective for a
period of time not to exceed the expiration date of the regulations in
this subpart.
(c) If an LOA expires prior to the expiration date of the
regulations in this subpart, HRCP may apply for and obtain a renewal of
the LOA.
(d) In the event of projected changes to the activity or to
mitigation and monitoring measures required by an LOA, HRCP must apply
for and obtain a modification of the LOA as described in Sec. 217.27.
(e) The LOA shall set forth the following information:
(1) Permissible methods of incidental taking;
(2) Means of effecting the least practicable adverse impact (i.e.,
mitigation) on the species, its habitat, and on the availability of the
species for subsistence uses; and
(3) Requirements for monitoring and reporting.
(f) Issuance of the LOA shall be based on a determination that the
level of taking will be consistent with the findings made for the total
taking allowable under the regulations in this subpart.
(g) Notice of issuance or denial of an LOA shall be published in
the Federal Register within thirty days of a determination.
Sec. 217.27 Renewals and modifications of Letters of Authorization.
(a) An LOA issued under Sec. Sec. 216.106 of this chapter and
217.26 for the activity identified in Sec. 217.20(a) shall be renewed
or modified upon request by the applicant, provided that:
(1) The proposed specified activity and mitigation, monitoring, and
reporting measures, as well as the anticipated impacts, are the same as
those described and analyzed for the regulations in this subpart; and
(2) NMFS determines that the mitigation, monitoring, and reporting
measures required by the previous LOA under the regulations in this
subpart were implemented.
(b) For LOA modification or renewal requests by the applicant that
include changes to the activity or the mitigation, monitoring, or
reporting that do not change the findings made for the regulations in
this subpart or result in no more than a minor change in the total
estimated number of takes (or distribution by species or years), NMFS
may publish a notice of proposed LOA in the Federal Register, including
the associated analysis of the change, and solicit public comment
before issuing the LOA.
(c) An LOA issued under Sec. Sec. 216.106 of this chapter and
217.26 for the activity identified in Sec. 217.20(a) may be modified
by NMFS under the following circumstances:
(1) HRCP may modify (including augment) the existing mitigation,
monitoring, or reporting measures (after consulting with NMFS regarding
the practicability of the modifications) if doing so creates a
reasonable likelihood of more effectively accomplishing the goals of
the mitigation and monitoring set forth in the regulations in this
subpart.
(i) Possible sources of data that could contribute to the decision
to modify the mitigation, monitoring, or reporting measures in a LOA:
(A) Results from HRCP's monitoring from previous years.
(B) Results from other marine mammal and/or sound research or
studies.
(C) Any information that reveals marine mammals may have been taken
in a manner, extent or number not authorized by the regulations in this
subpart or subsequent LOAs.
(ii) If, through adaptive management, the modifications to the
mitigation, monitoring, or reporting measures are substantial, NMFS
will publish a notice of proposed LOA in the Federal Register and
solicit public comment.
(2) If NMFS determines that an emergency exists that poses a
significant risk to the well-being of the species or stocks of marine
mammals specified in a LOA issued pursuant to Sec. Sec. 216.106 of
this chapter and 217.26, a LOA may be modified without prior notice or
opportunity for public comment. Notice would be published in the
Federal Register within thirty days of the action.
Sec. Sec. 217.28-217.29 [Reserved]
[FR Doc. 2020-29125 Filed 1-7-21; 8:45 am]
BILLING CODE 3510-22-P