[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





-----------------------------------------------------------------------





National Oceanic and Atmospheric Administration





-----------------------------------------------------------------------





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]]


-----------------------------------------------------------------------

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.

-----------------------------------------------------------------------

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:
    <bullet> 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:
    <bullet> Shutdown of construction activities under certain 
circumstances to avoid injury of marine mammals.
    <bullet> Required monitoring of the construction areas to detect 
the presence of marine mammals before beginning construction 
activities.
    <bullet> 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.
    <bullet> 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:
    <bullet> 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]);
    <bullet> Hampton Creek Entrance Channel (200 feet wide and is 
maintained at a depth of 12 feet MLLW);
    <bullet> Phoebus Channel (150 feet wide and is maintained at a 
depth of 12 feet MLLW); and
    <bullet> 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,

[[Page 1590]]

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

[[Page 1591]]

[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
------------------------------------------------------------------------
   Project design segment number and name          Construction area
------------------------------------------------------------------------
Segment 1a (Hampton)........................  Area 1.
Segment 1b (North Trestle-Bridges) \1\......  Area 2.
Segment 2a (Tunnel) \1\.....................  Area 3.

[[Page 1592]]

 
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.
------------------------------------------------------------------------
\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:
    <bullet> 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;
    <bullet> 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;
    <bullet> 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
    <bullet> 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:
    <bullet> A minimum 10-meter shutdown zone will be implemented for 
all species, pile sizes, and hammer types to prevent direct injury of 
marine mammals.
    <bullet> A 15-meter shutdown zone will be implemented for seals to 
prevent direct injury.
    <bullet> A 100-meter shutdown zone will be implemented for harbor 
porpoises when utilizing a DTH hammer and impact hammering to prevent 
direct injury.
    <bullet> 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:
    <bullet> 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.
    <bullet> A 35-meter shutdown zone will be implemented for harbor 
seals and gray seals to prevent direct injury.
    <bullet> An 85-meter shutdown zone will be implemented for harbor 
porpoise to prevent direct injury.
    <bullet> 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:
    <bullet> The bubble curtain must distribute air bubbles around 100 
percent of the piling perimeter for the full depth of the water column.
    <bullet> 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.
    <bullet> The bubble curtain shall be operated such that there is 
proper (equal) balancing of air flow to all bubblers.
    <bullet> 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:
    <bullet> Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density).
    <bullet> 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]]

    <bullet> Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors.
    <bullet> How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks.
    <bullet> Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat).
    <bullet> 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:
    <bullet> Independent PSOs (i.e., not construction personnel) who 
have no other assigned tasks during monitoring periods must be used;
    <bullet> 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;
    <bullet> Other PSOs may substitute education (degree in biological 
science or related field) or training for experience;
    <bullet> 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
    <bullet> HRCP must submit PSO Curriculum Vitae for approval by NMFS 
prior to the onset of pile driving.
    PSOs must have the following additional qualifications:
    <bullet> Ability to conduct field observations and collect data 
according to assigned protocols;
    <bullet> Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
    <bullet> Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    <bullet> 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
    <bullet> 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
    <bullet> Dates and times (begin and end) of all marine mammal 
monitoring.
    <bullet> 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).
    <bullet> 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).
    <bullet> 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.
    <bullet> Age and sex class, if possible, of all marine mammals 
observed.
    <bullet> PSO locations during marine mammal monitoring.
    <bullet> 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).
    <bullet> 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.
    <bullet> Number of marine mammals detected within the harassment 
zones, by species.
    <bullet> 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.
    <bullet> 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:
    <bullet> No serious injury or mortality is anticipated or 
authorized;
    <bullet> Authorized Level A harassment would be limited and of low 
degree;
    <bullet> The intensity of anticipated takes by Level B harassment 
is relatively low for all stocks;
    <bullet> The number of anticipated takes is very low for humpback 
whale, harbor porpoise, and gray seal;
    <bullet> 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;
    <bullet> The lack of anticipated significant or long-term negative 
effects to marine mammal habitat; and
    <bullet> 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:
    <bullet> Potential bottlenose dolphin takes in the project area are 
likely to be allocated among three distinct stocks;
    <bullet> 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;
    <bullet> 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
    <bullet> 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