[Federal Register Volume 88, Number 62 (Friday, March 31, 2023)]
[Rules and Regulations]
[Pages 19502-19542]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-06300]



[[Page 19501]]

Vol. 88

Friday,

No. 62

March 31, 2023

Part IV





Department of Commerce





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National Oceanic and Atmospheric Administration





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50 CFR Part 217





Taking and Importing Marine Mammals; Taking Marine Mammals Incidental 
to U.S. Navy Construction at Portsmouth Naval Shipyard, Kittery, Maine; 
Final Rule

  Federal Register / Vol. 88 , No. 62 / Friday, March 31, 2023 / Rules 
and Regulations  

[[Page 19502]]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 217

[Docket No. 230321-0081]
RIN 0648-BL78


Taking and Importing Marine Mammals; Taking Marine Mammals 
Incidental to U.S. Navy Construction at Portsmouth Naval Shipyard, 
Kittery, Maine

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

ACTION: Final rule; notification of issuance of Letter of 
Authorization.

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SUMMARY: NMFS, upon request from the U.S. Navy (Navy), hereby issues 
regulations to govern the unintentional taking of marine mammals 
incidental to construction at the Portsmouth Naval Shipyard in Kittery, 
Maine, over the course of 5 years (2023-2028). These regulations, which 
allow for the issuance of a Letter of Authorization (LOA) for the 
incidental take of marine mammals during the described activities and 
specified timeframes, prescribe the permissible methods of taking and 
other means of effecting the least practicable adverse impact on marine 
mammal species or stocks and their habitat, as well as requirements 
pertaining to the monitoring and reporting of such taking.

DATES: Effective from April 1, 2023, through March 31, 2028.

ADDRESSES: A copy of the Navy'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-us-navy-construction-portsmouth-naval-shipyard-kittery-maine-0. In case of problems accessing these 
documents, please call the contact listed below.

FOR FURTHER INFORMATION CONTACT: Reny Tyson Moore, Office of Protected 
Resources, NMFS, [email protected], (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Purpose and Need for Regulatory Action

    We received an application from the Navy requesting 5-year 
regulations and authorization to take multiple species of marine 
mammals. This rule establishes a framework under the authority of the 
MMPA (16 U.S.C. 1361 et seq.) to allow for the authorization of take by 
Level A and Level B harassment of marine mammals incidental to the 
Navy's construction activities related to the multifunctional expansion 
and modification of Dry Dock 1 at the Portsmouth Naval Shipyard in 
Kittery, Maine. Please see the Background section below for definitions 
of harassment.

Legal Authority for the 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 5 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 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 rule containing 5 year 
regulations, and for any subsequent Letters of Authorization (LOAs). As 
directed by this legal authority, this rule contains mitigation, 
monitoring, and reporting requirements.

Summary of Major Provisions Within the Regulations

    Following is a summary of the major provisions of this rule 
regarding the Navy's construction activities. These measures include:
     Required monitoring of the in-water construction areas to 
detect the presence of marine mammals before beginning in-water 
construction activities;
     Shutdown of in-water construction activities under certain 
circumstances to avoid injury of marine mammals;
     Soft start for impact pile driving to allow marine mammals 
the opportunity to leave the area prior to beginning impact pile 
driving at full power; and
     Implementation of a bubble curtain during rock hammering 
and down-the-hole (DTH) cluster drilling to reduce underwater noise 
impacts.

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct 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 and either regulations 
are proposed or, if the taking is limited to harassment, a notice of a 
proposed incidental take authorization is provided to the public for 
review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the mitigation, 
monitoring and reporting of the takings are set forth. The definitions 
of all applicable MMPA statutory terms cited above are included in the 
relevant sections below.

Summary of Request

    On May 9, 2022, NMFS received a request from the Navy for 
authorization to take marine mammals incidental to construction 
activities related to the multifunctional expansion and modification of 
Dry Dock 1 at Portsmouth Naval Shipyard in Kittery, Maine. We provided 
comments on the application, and the Navy submitted revised versions 
and responses to our comments on July 5, 2022, August 15, 2022, August 
19, 2022, and August 25, 2022, with the latter version deemed adequate 
and complete. On September 1, 2022, we published a notice of receipt of 
the Navy's application in the Federal Register (87 FR 53731), 
requesting comments and information related to the request. During the 
30-day comment period, we received two supportive letters from private 
citizens.
    On October 19 and 25, 2022, NMFS was notified by the Navy of 
project modifications and shifting Fleet submarine schedules that 
required the resequencing of certain activities associated with the 
construction at Dry Dock 1 in order to accommodate the modifications 
and meet the new vessel docking demands. On October 31, 2022, the Navy 
submitted an addendum to its

[[Page 19503]]

application describing these changes. We published a notice of the 
proposed rulemaking in the Federal Register on January 18, 2023 (88 FR 
3146) incorporating these changes and requested comments and 
information from the public. Please see Comments and Responses below. 
The regulations are valid for 5 years, from April 1, 2023 through March 
31, 2028, and authorize the Navy to take five species of marine mammals 
by Level A and Level B harassment incidental to construction activities 
related to the multifunctional expansion and modification of Dry Dock 1 
at the Portsmouth Naval Shipyard in Kittery, Maine. Neither the Navy 
nor NMFS expect serious injury or mortality to result from this 
activity.
    NMFS previously issued five IHAs to the Navy for waterfront 
improvement work at the Portsmouth Naval Shipyard: in 2016 (81 FR 
85525, November 28, 2016), 2018 (83 FR 3318, January 24, 2018), 2019 
(84 FR 24476, May 28, 2019), a renewal of the 2019 IHA (86 FR 14598, 
March 17, 2021), and in 2022 (87 FR 19886, April 6, 2022). The most 
recent IHA (87 FR 19886) provided authorization to take marine mammals 
during the first year of the construction project described in this 
final rule. As required, the applicant provided monitoring reports 
(available at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities) 
which confirm that the applicant has implemented the required 
mitigation and monitoring, and which also shows that no impacts of a 
scale or nature not previously analyzed or authorized have occurred as 
a result of the activities conducted.

Description of the Specified Activity

Overview

    Multifunctional Expansion of Dry Dock 1 (P-381) is one of three 
projects that support the overall expansion and modification of Dry 
Dock 1, located in the western extent of the Portsmouth Naval Shipyard. 
The two additional projects, construction of a super flood basin (P-
310) and extension of portal crane rail and utilities (P-1074), are 
currently under construction. In-water work associated with these 
projects was completed under the aforementioned separate IHAs issued by 
NMFS. The projects have been phased to support Navy mission schedules. 
P-381 will be constructed within the same footprint of the super flood 
basin over an approximate 7-year period, during which 5 years of in-
water work will occur. An IHA was issued by NMFS for the first year of 
P-381 construction activities between April 1, 2022 and March 31, 2023 
(87 FR 19866, April 6, 2022). This request is associated with the 
remaining 4 years of P-381 in-water construction activities planned to 
occur from April 1, 2023 through March 31, 2028, as well as for 
additional in-water construction activities associated with the removal 
of emergency repair components of the super flood basin that will occur 
during the period of effectiveness for the regulations. Although the 
in-water construction described in this rule is anticipated to be 
completed by December 2026, unanticipated schedule delays could result 
in the Navy conducting construction activity over the full 5 years.
    The purpose of the Navy's project (P-381) is to modify the super 
flood basin to create two additional dry docking positions (Dry Dock 1 
North and Dry Dock 1 West) in front of the existing Dry Dock 1 East. 
The Navy's specified activity also includes emergency repairs of the P-
310 super flood basin. Construction activities will include the 
excavation and/or installation of 1,118 holes, 198 shafts, and 580 
sheet piles via impact and vibratory pile driving, hydraulic rock 
hammering, rotary drilling, and mono and cluster DTH. The construction 
activities are expected to require approximately 2,498 days if the 
activities are considered independently over the 5-year period. 
However, the actual construction duration is expected to be within 4 
years as many of the construction activities will occur concurrently.

Dates and Duration

    The in-water construction activities associated with this rule are 
anticipated to begin in April 2023 and proceed to December 2026 (4 
years); however, the incidental take authorization is valid for 5 years 
in the event of unexpected scheduled delays. In-water construction 
activities will occur consecutively over a 4-year period. The Navy 
plans to conduct all in-water work activities with expected potential 
for incidental harassment of marine mammals during daylight hours.
    Table 1 provides the estimated schedule and production rates for P-
381 construction activities. Many of the activities included in Table 1 
will span across multiple construction years and/or will occur 
concurrently. Because of mission requirements and operational schedules 
at the dry docking positions and berths, this schedule is subject to 
change. In-water construction activities for P-381 will occur 
consecutively over a 4-year period. Note, for the purposes of this 
analysis, the construction years are identified as years 2 through 5; 
Year 1 of the Navy's construction activities is currently ongoing in 
association with a previously issued IHA (87 FR 19886, April 6, 2022). 
Vibratory pile driving and extraction is assumed to occur for 141 days. 
Impact pile driving will occur for 34 days. DTH excavation (mono-hammer 
and cluster drill) will occur for 1,446 days. Rotary drilling will 
occur for 238 days (assuming that casings and sockets for cluster 
drills will be set, excavated, and removed in a single day). Rock 
hammering will occur for 277 days. Note that pile driving days are not 
necessarily consecutive, and certain activities may occur at the same 
time, decreasing the total number of actual in-water construction days. 
The contractor could be working in more than one area of the berths at 
a time.

                                    Table 1--In-Water Construction Activities
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                              Total amount and
 Activity                      estimated dates      Activity                        Daily production     Total
    ID          Activity        (construction       component          Method             rate        production
                                  years *)                                                               days
----------------------------------------------------------------------------------------------------------------
A1 \1\....  Center Wall--     Drill 18 shafts   Install 102-inch  Rotary drill....  1 shaft/day 1         \4\ 18
             Install           Apr 23 \3\ to     diameter outer                      hour/day.
             Foundation        Aug 23 (2).       casing.
             Support Piles.
A2 \1\....                                      Pre-drill 102-    Rotary drill....  1 shaft/day 9         \4\ 18
                                                 inch diameter                       hours/day.
                                                 socket.
A3 \1\....                                      Remove 102-inch   Rotary drill....  1 casing/day 15       \4\ 18
                                                 outer casing.                       minutes/casing.
A4 \1\....                                      Drill 78-inch     Cluster drill     6.5 days/shaft       \4\ 117
                                                 diameter shaft.   DTH.              10 hours/day.
R \1\.....  Dry Dock 1 North  Install 48 sheet  28-inch wide Z-   Impact with       8 sheets/day 5         \4\ 6
             Entrance--Insta   piles Apr 23      shaped sheets.    initial           minutes and 300
             ll Temporary      \3\ to May 23                       vibratory set.    blows/pile.
             Cofferdam.        (2).

[[Page 19504]]

 
1.........  Berth 11--Remove  Remove 112        Concrete shutter  Hydraulic rock    5 hours/day.....      \4\ 56
             Shutter Panels.   panels Apr 23     panels.           hammering.
                               \3\ to May 23
                               (2).
2.........  Berth 1--Remove   Remove 168 sheet  25-inch-wide Z-   Vibratory         4 piles/day.....      \4\ 42
             Sheet Piles.      piles Apr 23      shaped.           extraction.
                               \3\ to Jun 24
                               (2, 3).
3.........  Berth 1--Remove   2,800 cubic       Removal of        Hydraulic rock    2.5 hours/day...      \4\ 47
             Granite Block     yards (cy) Apr    granite blocks.   hammering.
             Quay Wall.        23 \3\ to Jun
                               24 (2, 3).
4.........  Berth 1--Top of   320 linear feet   Mechanical        Hydraulic rock    10 hours/day....      \4\ 74
             Wall Removal      (lf) Apr 23 \3\   concrete          hammering.
             for Waler         to Jun 24 (2,     removal.
             Installation.     3).
5.........  Berth 1--Install  Install 28 sheet  28-inch-wide Z-   Impact with       4 piles/day 5          \4\ 8
             southeast         piles Apr 23 to   shaped.           initial           minutes/pile
             corner Support    Jul 23 (2).                         vibratory set.    and 300 blows/
             of Excavation                                                           pile.
             (SOE).
6.........  Berth 11--        700 cy Apr 23     Excavate Bedrock  Hydraulic rock    12 hours/day....  \3\ \4\ 60
             Mechanical Rock   \3\ to Aug 23                       hammering.
             Removal at        (2).
             Basin Floor.
7.........  Berth 11 Face--   Drill 924 relief  4-6 inch          DTH mono-hammer.  27 holes/day 22       \4\ 35
             Mechanical Rock   holes Apr 23      diameter holes.                     min/hole.
             Removal at        \3\ to Aug 23
             Basin Floor.      (2).
8.........  Install           Install 14 sheet  28-inch-wide Z-   Impact with       4 piles/day 5              4
             Temporary         piles Apr 23 to   shaped.           initial           minutes/pile
             Cofferdam         Jun 23 (2).                         vibratory set.    and 300 blows/
             Extension.                                                              pile.
9a........  Gantry Crane      Drill 16 shafts   Set 102-inch      Rotary drill....  1 shaft/day 1             16
             Support Piles     Apr 23 to Aug     diameter casing.                    hours/day.
             at Berth 1 West.  23 (2).
9b........                                      Pre-drill 102-    Rotary drill....  1 shaft/day 9             16
                                                 inch rock                           hours/day.
                                                 socket.
9c........                                      Remove 102-inch   Rotary drill....  1 casing/day 15           16
                                                 casing.                             minutes/casing.
9d........                                      72-inch diameter  Cluster drill     5 days/shaft 10           80
                                                 shafts.           DTH.              hours/day.
10 \2\....  Berth 1--         300 cy Apr 23     Excavate Bedrock  Hydraulic rock    13 cy/day 12          \5\ 25
             Mechanical Rock   \3\ to Sep 23                       hammering.        hours/day.
             Removal at        (2).
             Basin Floor.
11........  Dry Dock 1 North  Drill 50 rock     9-inch diameter   DTH mono-hammer.  2 holes/day 5         \4\ 25
             Entrance--Drill   anchors Apr 23    holes.                              hours/hole.
             Tremie Tie        \3\ to Oct 23
             Downs.            (2).
12........  Center Wall--     Install 15 sheet  28-inch wide Z-   Impact with       4 piles/day 5              4
             Install Tie-In    piles Apr 23 to   shaped.           initial           minutes/pile
             to Existing       Dec 23 (2).                         vibratory set.    and 300 blows/
             West Closure                                                            pile.
             Wall.
13a.......  Dry Dock 1        Drill 20 shafts   Set 102-inch      Rotary drill....  1 shaft/day 1             20
             North--Temporar   May 23 to Nov     diameter casing.                    hours/day.
             y Work Trestle    24 (2, 3).
             Piles.
13b.......                                      Pre-drill 102-    Rotary drill....  1 shaft/day 9             20
                                                 inch rock                           hours/day.
                                                 socket.
13c.......                                      Remove 102-inch   Rotary drill....  1 casing/day 15           20
                                                 casing.                             minutes/casing.
13d.......                                      84-inch diameter  Cluster drill     3.5 days/shaft            70
                                                 shafts.           DTH.              10 hours/day.
14........  Dry Dock 1        Remove 20 piles   84-inch diameter  Rotary drill....  1 day/pile 15             20
             North--Remove     May 23 to Nov     drill piles.                        minutes/pile.
             Temporary Work    24 (2, 3).
             Trestle Piles.
15a.......  Dry Dock 1        Drill 18 shafts   Set 84-inch       Rotary drill....  1 shaft/day 1             18
             North--Install    May 23 to Nov     casing.                             hours/day.
             Leveling Piles    24 (2, 3).
             (Diving Board
             Shafts).
15b.......                                      Pre-drill 84-     Rotary drill....  1 shaft/day 9             18
                                                 inch rock                           hours/day.
                                                 socket.
15c.......                                      Remove 84-inch    Rotary drill....  1 casing/day 15           18
                                                 casing.                             minutes/casing.
15d.......                                      78-inch diameter  Cluster drill     7.5 days/shaft           135
                                                 shaft.            DTH.              10 hours/day.
16a.......  Wall Support      Drill 20 shafts   Set 102-inch      Rotary drill....  1 shaft/day 1             20
             Shafts for Dry    Jun 23 to Nov     diameter casing.                    hours/day.
             Dock 1 North      24 (2, 3).
             (Berth 11 Face
             and Head Wall).
16b.......                                      Pre-drill 102-    Rotary drill....  1 shaft/day 9             20
                                                 inch rock                           hours/day.
                                                 socket.
16c.......                                      Remove 102-inch   Rotary drill....  1 casing/day 15           20
                                                 casing.                             minutes/casing.
16d.......                                      Drill 78-inch     Cluster drill     7.5 days/shaft           150
                                                 diameter shaft.   DTH.              10 hours/day.
17a.......  Foundation        Drill 23 shafts   Set 126-inch      Rotary drill....  1 shaft/day 1             23
             (Floor) Shafts    Jun 23 to Nov     diameter Casing.                    hours/day.
             for Dry Dock 1    24 (Const.
             North             years 2, 3).
             (Foundation
             Support Piles).
17b.......                                      Pre-drill 126-    Rotary drill....  1 shaft/day 9             23
                                                 inch rock                           hours/day.
                                                 socket.
17c.......                                      Remove 126-inch   Rotary drill....  1 casing/day 60           23
                                                 casing.                             minutes/casing.
17d.......                                      Drill 108-inch    Cluster drill     8.5 days/shaft           196
                                                 diameter shafts.  DTH.              10 hours/day.
18........  Berth 11 End      Remove 60 sheet   28-inch wide Z-   Vibratory         8 piles/day 5         \5\ 10
             Wall--Remove      piles Jul 23 to   shaped.           extraction.       minutes/pile.
             Temporary Guide   Aug 23 (2, 3).
             Wall.
19........  Remove Berth 1    Remove 28 sheet   28-inch-wide Z-   Vibratory         8 piles/day 5          \4\ 5
             southeast         piles Jul 23 to   shaped.           extraction.       minutes/pile.
             corner SOE.       Sep 23 (2).

[[Page 19505]]

 
20 \2\....  Removal of Berth  Remove 108 sheet  28-inch-wide Z-   Vibratory         6 piles/day 5             18
             1 Emergency       piles Apr 23      shaped.           extraction.       minutes/pile.
             Repair Sheet      \3\ to Jul 23
             Piles.            (2).
21 \2\....  Removal of Berth  500 cy Apr 23     Mechanical        Hydraulic rock    4 hours/day.....          15
             1 Emergency       \3\ to Aug 23     concrete          hammering.
             Repair Tremie     (2).              removal.
             Concrete.
22........  Center Wall       Install 72 rock   9-inch diameter   DTH mono-hammer.  2 holes/day 5             36
             Foundation--Dri   anchors Aug 23    holes.                              hours/hole.
             ll in Monolith    to May 24 (2,
             Tie Downs.        3).
23........  Center Wall--     Remove 16 sheet   28-inch-wide Z-   Vibratory         8 piles/day 5          \5\ 3
             Remove Tie-In     piles \6\ Aug     shaped.           extraction.       minutes/pile.
             to Existing       23 to Aug 24
             West Closure      (2, 3).
             Wall (Dry Dock
             1 North) \4\.
24........  Center Wall       Install 23 sheet  28-inch wide Z-   Impact with       2 piles/day 5             12
             East--Sheet       piles Aug 23 to   shaped.           initial           minutes/pile
             Pile Tie-In to    Oct 24 (2, 3).                      vibratory set.    and 300 blows/
             Existing Wall.                                                          pile.
25........  Remove Tie-In to  Remove 15 sheet   28-inch wide Z-   Vibratory         8 piles/day 5          \5\ 3
             West Closure      pile Dec 23 to    shaped.           extraction.       minutes/pile.
             Wall (Dry Dock    Dec 24 (2, 3).
             1 West).
26........  Remove Center     Remove 23 sheet   28-inch wide Z-   Vibratory         8 piles/day 5         \5\ 12
             Wall East--       piles Dec 23 to   shaped.           extraction.       minutes/pile.
             Sheet Pile Tie-   Dec 24 (2, 3).
             In to Existing
             Wall (Dry Dock
             1 West).
27........  Dry Dock 1 North  Remove 96 sheet   28-inch wide Z-   Vibratory         8 piles/day 5             12
             Entrance--Remov   piles Jan 24 to   shaped.           extraction.       minutes/pile.
             e Temporary       Sep 24 (Const.
             Cofferdam.        years 2, 3).
28........  Remove Temporary  Remove 14 sheet   28-inch wide Z-   Vibratory         8 piles/day 5              2
             Cofferdam         piles Jan 24 to   shaped.           extraction.       minutes/pile.
             Extension.        Sep 24 (2, 3).
29a.......  Dry Dock 1 West-- Drill 20 shafts   Set 102-inch      Rotary drill....  1 shaft/day 1             20
             Install           Apr 24 to Feb     diameter casing.                    hours/day.
             Temporary Work    26 (3, 4).
             Trestle Piles.
29b.......                                      Pre-drill 102-    Rotary drill....  1 shaft/day 9             20
                                                 inch rock                           hours/day.
                                                 socket.
29c.......                                      Remove 102-inch   Rotary drill....  1 casing/day 15           20
                                                 casing.                             minutes/casing.
29d.......                                      84-inch diameter  Cluster drill     3.5 days/shaft            70
                                                 shafts.           DTH.              10 hours/day.
30........  Dry Dock 1 West-- Remove 20 piles   84-inch diameter  Rotary drill....  1 day/pile 15             20
             Remove            Apr 24 to Feb     piles.                              minutes/pile.
             Temporary Work    26 (3, 4).
             Trestle Piles.
31a.......  Wall Support      Drill 22 shafts   Set 102-inch      Rotary drill....  1 shaft/day 1             22
             Shafts for Dry    Jun 24 to Feb     diameter casing.                    hours/day.
             Dock 1 West       26 (3, 4).
             (Berth 1 Face).
31b.......                                      Pre-drill 102-    Rotary drill....  1 shaft/day 9             22
                                                 inch rock                           hours/day.
                                                 socket.
31c.......                                      Remove 102-inch   Rotary drill....  1 casing/day 15           22
                                                 casing.                             minutes/casing.
31d.......                                      78-inch diameter  Cluster drill     7.5 days/shaft           165
                                                 shaft.            DTH.              10 hours/day.
32a.......  Foundation        Drill 23 shafts   Set 126-inch      Rotary drill....  1 shaft/day 1             23
             (Floor) Shafts    Jun 24 to Feb     casing.                             hours/day.
             for Dry Dock 1    26 (3, 4).
             West
             (Foundation
             Support Piles).
32b.......                                      Pre-drill 126-    Rotary drill....  1 shaft/day 9             23
                                                 inch rock                           hours/day.
                                                 socket.
32c.......                                      Remove 126-inch   Rotary drill....  1 casing/day 15           23
                                                 casing.                             minutes/casing.
32d.......                                      Drill 108-inch    Cluster drill     8.5 days/shaft           196
                                                 diameter shaft.   DTH.              10 hours/day.
33a.......  Dry Dock 1 West-- Drill 18 shafts   Set 84-inch       Rotary Drill....  1 shaft/day 1             18
             Install           Jun 24 to Feb     casing.                             hours/day.
             Leveling Piles    26 (3, 4).
             (Diving Board
             Shafts).
33b.......                                      Pre-drill 84-     Rotary drill....  1 shaft/day 9             18
                                                 inch rock                           hours/day.
                                                 socket.
33c.......                                      Remove 84-inch    Rotary drill....  1 casing/day 15           18
                                                 casing.                             minutes/casing.
33d.......                                      Drill 78-inch     Cluster drill     7.5 days/shaft           135
                                                 diameter shaft.   DTH.              10 hours/day.
34........  Dry Dock 1        Install 36 rock   9-inch diameter   DTH mono-hammer.  2 holes/day 5             18
             North--Tie        anchors Jul 24    holes.                              hours/hole.
             Downs.            to Jul 25 (3,
                               4).
35........  Dry Dock 1 West-- Install 36 rock   9-inch diameter   DTH mono-hammer.  2 holes/day 5             18
             Install Tie       anchors Dec 25    hole.                               hours/hole.
             Downs.            to Dec 26 (4,
                               5).
----------------------------------------------------------------------------------------------------------------
Total excavated holes/        1,118/198/580...  ................  ................  ................       2,498
 drilled shafts/sheet piles.
----------------------------------------------------------------------------------------------------------------
* Note: for the purposes of this analysis, the construction years are identified as years 2 through 5; potential
  marine mammal takes incidental to Year 1 of the Navy's construction activities were authorized under a
  previously issued IHA (87 FR 19886, April 6, 2022).
\1\ These activities were not included in the original application made available for public review during the
  Notice of Receipt comment period (NOR; 87 FR 53731), but have been added due to changes needed in the
  construction schedule.
\2\ These activities were included in the original application, but the amount of activity has been modified due
  to changes needed in the construction schedule.
\3\ These activities began in construction year 1.
\4\ These activities began in year 1. Only the number of production days occurring in construction years 2
  through 6 are presented.
\5\ Additional production days are included to account for equipment repositioning.
\6\ Sheet piles were installed in construction year 1.


[[Page 19506]]

Specific Geographic Region

    The shipyard is located in the Piscataqua River in Kittery, Maine. 
The Piscataqua River originates at the boundary of Dover, New 
Hampshire, and Eliot, Maine (Figure 1). The river flows in a 
southeasterly direction for 2,093 meters (m) (13 miles (mi)) before 
entering Portsmouth Harbor and emptying into the Atlantic Ocean. The 
lower Piscataqua River is part of the Great Bay Estuary system and 
varies in width and depth. Many large and small islands break up the 
straight-line flow of the river as it continues toward the Atlantic 
Ocean. Seavey Island, the location of the specified activities, is 
located in the lower Piscataqua River approximately 500 m, 1,640 feet 
(ft) from its southwest bank, 200 m (656 ft) from its north bank, and 
approximately 4 kilometers (km) (2.5 mi) from the mouth of the river.
    Water depths in the project area range from 6.4 m (21 ft) to 11.9 m 
(39 ft) at Berths 11, 12, and 13. Water depths in the lower Piscataqua 
River near the project area range from 4.6 m (15 ft) in the shallowest 
areas to 21 m (69 ft) in the deepest areas. The river is approximately 
914 m (3,300 ft) wide near the project area, measured from the Kittery 
shoreline north of Wattlebury Island to the Portsmouth shoreline west 
of Peirce Island. The furthest direct line of sight from the project 
area is 1,287 m (0.8 mi) to the southeast and 418 m (0.26 mi) to the 
northwest.
    The nearshore environment of the Shipyard is characterized by a mix 
of hard bottom, gravel, soft sediments, rock outcrops, and rocky 
shoreline associated with fast tidal currents near the installation. 
The nearshore areas surrounding Seavey Island are predominately hard 
bottom (65 percent of benthic habitat) and gravel (26 percent) habitat, 
with only 9 percent soft bottom sediments within the surveyed area 
around Seavey Island (Tetra Tech, 2016). Much of the shoreline in the 
project area is composed of hard shores (rocky intertidal). In general, 
rocky intertidal areas consist of bedrock that alternates between 
marine and terrestrial habitats, depending on the tide. Rocky 
intertidal areas consist of ``bedrock, stones, or boulders that singly 
or in combination cover 75 percent or more of an area that is covered 
less than 30 percent by vegetation'' (Federal Geographic Data 
Committee, 2013).
    The lower Piscataqua River is home to Portsmouth Harbor and is used 
by commercial, recreational, and military vessels. Between 150 and 250 
commercial shipping vessels transit the lower Piscataqua River each 
year (Magnusson et al., 2012). Commercial fishing vessels are also very 
common in the river year-round, as are recreational vessels, which are 
more common in the warmer summer months. The shipyard is a dynamic 
industrial facility situated on an island with a narrow separation of 
waterways between the installation and the communities of Kittery and 
Portsmouth (Figure 2). The predominant noise sources from Shipyard 
industrial operations consist of dry dock cranes; passing vessels; and 
industrial equipment (e.g., forklifts, loaders, rigs, vacuums, fans, 
dust collectors, blower belts, heating, air conditioning, and 
ventilation (HVAC) units, water pumps, and exhaust tubes and lids). 
Other components such as construction, vessel ground support equipment 
for maintenance purposes, vessel traffic across the Piscataqua River, 
and vehicle traffic on the shipyard's bridges and on local roads in 
Kittery and Portsmouth produce noise, but such noise generally 
represents a transitory contribution to the average noise level 
environment (Blue Ridge Research and Consulting (BRRC), 2015; ESS 
Group, 2015). Ambient sound levels recorded at the shipyard are 
considered typical of a large outdoor industrial facility and vary 
widely in space and time (ESS Group, 2015).
BILLING CODE 3510-22-P

[[Page 19507]]

[GRAPHIC] [TIFF OMITTED] TR31MR23.000


[[Page 19508]]


[GRAPHIC] [TIFF OMITTED] TR31MR23.001

BILLING CODE 3510-22-C

[[Page 19509]]

Detailed Description of the Specified Activity

    The Navy's P-381 project will modify the super flood basin to 
create two additional dry docking positions (Dry Dock 1 North and Dry 
Dock 1 West) in front of the existing Dry Dock 1 East. The super flood 
basin provides the starting point for the P-381 work. Several steps are 
required to convert the super flood basin to a dry dock with two 
positions fully capable of supporting the maintenance of submarines 
while maintaining access to the existing interior dry dock (Dry Dock 1 
East). The dry dock positions (including the center wall) will be 
constructed using large precast segments (referred to as monoliths) 
that require both sidewall and base support. The monoliths will be 
manufactured offsite and transported to the construction site. Segments 
will be floated and/or lifted into place to create the center wall, 
followed by Dry Dock 1 North, and finally Dry Dock 1 West. Once the 
monoliths are set and grouted in place, the respective dry docks can be 
dewatered allowing the remaining interior construction to be performed 
in dry conditions.
    P-381 years 2 through 5 (i.e., the time period of the Navy's 
specified activity for this rule) construction activities will complete 
bedrock removal and the preparation of the walls and floors of the 
super flood basin to support the placement of the monoliths and the 
construction of the two dry dock positions. Most of the in-water 
construction will occur behind the existing super flood basin walls 
that will act as a barrier to sound and will contain underwater noise 
to within a small portion of the Piscataqua River. However, the west 
closure wall will be removed in order to install the Dry Dock 1 North 
entrance structure and caisson. In addition, the caissons may not 
always be in place throughout in-water construction. As such, the 
analyses presented herein conservatively assume the west closure wall, 
as well as the future caissons, will not be present throughout in-water 
construction activities.
    The Navy's request also considers emergency repairs of the P-310 
super flood basin. During P-310 super flood testing in January 2022, 
excessive exfiltration (i.e., transport of material outside of the 
basin) was observed along Berths 1 and 2 and between the west closure 
wall and super flood basin entrance structure. Emergency structural 
repairs were required to reduce excessive transport of material through 
the berths and west closure wall/entrance structure and prevent further 
damage. As a result, 216 28-inch Z-shaped sheet piles were installed 
along the Berth 1 face. After installation, these sheet piles were cut 
off approximately 3 m (10 ft) above the mudline and concrete was tremie 
placed behind them to plug any gaps in the existing structure that 
contributed to the exfiltration. The removal of these 216 Berth 1 
emergency repair piles and excess tremie concrete (approximately 382 
cubic meters, 500 cubic yards (cy)) will be completed during this LOA 
period and are accounted for in the Navy's request. Similarly, 10 28-
inch wide, Z-shaped sheet piles were installed between the super flood 
basin entrance structure and the west closure wall, cut off 
approximately 3 m (10 ft) above the mudline, and had concrete tremie 
placed behind them. These 10 sheet piles will be removed during the P-
381 year 1 IHA period (covered under the IHA issued by NMFS for the 
first year of P-381 construction activities; 87 FR 19866, April 6, 
2022).
    Several additional preparatory activities (e.g., torch cutting, 
dredging, etc.) will not create noise expected to result in harassment 
of marine mammals. Noise created during dredging of sediment and 
demolition debris (e.g., bedrock, granite blocks, concrete) is unlikely 
to exceed that generated by other normal shipyard activities and is not 
expected to result in incidental take of marine mammals. Activities 
such as grouting (i.e., pouring of concrete) and torch cutting are not 
noisy by design and will not result in incidental take of marine 
mammals. These activities are not addressed in the analyses of noise 
producing actions in the Navy's request, and are not considered by NMFS 
in our analysis, but are included in the work descriptions to clarify 
the construction progression.

P-381 In-Water Construction Activities

    The work remaining for P-381 can be generally grouped into five 
categories for ease of explanation: temporary structures, mechanical 
bedrock removal, continued demolition of super flood basin wall 
components, center wall tie-downs, and dry dock foundation and gantry 
crane support. Each category involves one or more activities expected 
to generate noise that could result in injury or harassment of marine 
mammals. Some of these activities are a continuation of work started in 
year 1, which were covered under a separate IHA issued by NMFS on April 
6, 2022 (87 FR 19886).
    Temporary Structures--Several temporary structures will be 
installed and removed to facilitate the construction of the dry docks. 
The conversion of the existing west closure wall to the Dry Dock 1 
North entrance requires reinforcement of the section of the west 
closure wall that will become the new dry dock entrance. The existing 
west closure wall structure will be surrounded by a temporary 
cofferdam. The cofferdam will be constructed with 48 28-inch wide, Z-
shaped sheet piles. The sheet piles will be installed using an initial 
vibratory set followed by driving with impact hammers to refusal.
    The temporary guide wall along the Berth 11 end wall installed 
during year 1 (60 28-inch wide, Z-shaped sheet piles) will be removed 
with a vibratory hammer. An extension to the temporary cofferdam around 
the Dry Dock 1 entrance structure installed during P-381 year 1 will 
also be constructed. The extension will consist of 14 28-inch wide, Z-
shaped sheet piles. The extension and the cofferdam (96 28-inch wide, 
Z-shaped sheet piles) will be removed in 2024 using a vibratory hammer.
    A temporary work trestle will be constructed to support the 
excavation of large shafts within the individual dry docking positions. 
The trestle will be installed in Dry Dock 1 North first and then 
relocated to Dry Dock 1 West. The trestle system will be supported by 4 
84-inch steel pipe piles and will be relocated five times within each 
dry dock. As a result, the piles will be installed and removed 20 times 
in Dry Dock 1 North and 20 times in Dry Dock 1 West. The piles will be 
installed with a cluster drill consisting of multiple DTH hammers and 
removed with a rotary drill. Before the cluster drill will be deployed, 
a 102-inch casing will be set into bedrock and a 5-ft (1.5-m) deep rock 
socket will be excavated with a rotary drill (see Figure 1-4 in the 
Navy's application). The socket will be filled with concrete and a 
second, 84-inch casing will be installed inside the larger casing and 
set in the concrete. No drilling will be required to install the second 
casing. The outer casing will then be removed with a rotary drill. The 
84-inch diameter cluster drill will operate independently inside the 
second casing to excavate the shaft. Once the shaft is drilled the 
inner casing will be removed by torch cutting.
    A temporary tie-in consisting of 15 28-inch wide, Z-shaped sheet 
piles will be installed between the center wall foundation and the west 
closure wall at Dry Dock 1 West. Twenty-three 28-inch wide, Z-shaped 
sheet piles will also be installed on the easterly end of Dry Dock 1 
West to provide a similar temporary tie-in to the center wall 
foundation near the entrance to Dry

[[Page 19510]]

Dock 1 East. The sheet piles will be installed using an initial 
vibratory set followed by driving with impact hammers. These tie-ins 
will be removed using a vibratory hammer along with the Dry Dock 1 
North tie-in to the west closure wall (16 28-inch wide, Z-shaped sheet 
piles) that was installed under the P-381 year 1 IHA (87 FR 19886).
    To support excavation activities along Berth 1, 28 28-inch wide, Z-
shaped sheet piles will be installed at the southeast corner of the 
berth using a combination of vibratory and impact hammers. These piles 
will be removed using a vibratory hammer.
    Mechanical Bedrock Removal--Mechanical removal of bedrock will be 
completed by the end of 2023 using various methods appropriate for the 
removal location and as needed to avoid damage to adjacent structures. 
Bedrock removal will occur along the Berth 11 face and abutment and 
along Berth 1.
    Bedrock will be removed by breaking it up with a hydraulic hammer 
(i.e., hoe ram or breaker). To protect adjacent structures during 
mechanical bedrock removal, 924 4-6-inch diameter relief holes will be 
drilled using a DTH mono-hammer. A total of approximately 918 cubic 
meters (1,200 cy) of bedrock are anticipated to be removed.
    Demolition of Super Flood Basin Wall Components--Demolition of 
existing wall components will include the removal of shutter panels, 
granite quay walls, sheet piles, and concrete making up the super flood 
basin. Demolition of existing wall structures will be conducted using a 
rock hammer. Specifically, the remaining sections of the existing 
concrete shutter panels making up the face of Berth 11 (112 panels), 
portions of the granite block quay wall (2,141 cm, 2,800 cy) at Berth 
1, and the remaining existing sheet pile wall at Berth 1 (168 25-inch 
wide, Z-shaped sheet piles) will be removed.
    The installation of a structural support waler (steel beam) at 
Berth 1 will also be completed. To complete the installation of the 
waler, about 98 m (320 linear ft) of concrete wall will be demolished 
using a hydraulic rock hammer.
    Center Wall Tie-downs--Additional work in the center wall area will 
involve the installation of support tie downs for future tremie 
concrete work. The tie downs require the placement of a total of 194 
rock anchors requiring 9-inch diameter holes. The rock anchors will be 
installed using a DTH mono-hammer.
    Dry Dock and Gantry Crane Support--The location of the future 
center wall requires reinforcement to allow placement of the large pre-
cast monolith structures forming the separation between the two new dry 
docking positions. Specifically, the floor of the existing basin must 
be able to provide an adequate foundation for the pre-cast monoliths 
that will make up the dry dock interiors and center wall. The basin 
floor will be reinforced by excavating 18 78-inch diameter shafts 
throughout the footprint of the center wall that will be filled with 
concrete to create the structural support piles for the center wall. 
The shafts will be excavated using a cluster drill consisting of 
multiple DTH mono-hammers. Before the cluster drill is deployed, a 102-
inch diameter casing will be set into bedrock and a 1.5 m (5 ft) deep 
rock socket will be excavated using a 102-inch diameter rotary drill 
(see Figure 1-4 of the Navy's application). The rock socket will be 
filled with concrete and a second, 78-inch diameter casing will be 
installed inside the 102-inch casing and set in the concrete. No 
drilling is required to install the second casing. The 102-inch 
diameter outer casing will then be removed with a rotary drill.
    The future Dry Dock 1 North and Dry Dock 1 West require significant 
structural reinforcement to provide an adequate foundation for the 
installation of the large pre-cast monolith structures forming the dry 
dock interior. Reinforcement of the individual dry dock foundations and 
walls will begin first at Dry Dock 1 North and, once completed, 
continue at Dry Dock 1 West. Twenty 78-inch diameter shafts will be 
excavated along the Berth 11 face and head wall to support the walls of 
Dry Dock 1 North. Along the floor of Dry Dock 1 North, 23 108-inch 
diameter shafts will be excavated for the installation of the 
foundation support piles and 18 78-inch diameter shafts will be 
excavated for the installation of leveling piles (i.e., diving board 
shafts).
    The dry dock foundation and wall support pile and leveling pile 
shafts will be filled with concrete to create the support piles for the 
dry dock walls and floors. The shafts will be excavated using a cluster 
drill consisting of multiple DTH hammers in the same manner as 
previously described for the temporary work trestle piles. Once the 
wall and foundation support piles and leveling piles for Dry Dock 1 
North have been installed, foundation and wall support piles and 
leveling piles will be installed for Dry Dock 1 West. Twenty-two 78-
inch diameter shafts will be excavated along the Berth 1 face to 
support the walls of Dry Dock 1 West. Twenty-three 108-inch diameter 
shafts will be excavated along the floor of Dry Dock 1 West for the 
installation of foundation support piles and 18 78-inch shafts will be 
excavated for the installation of leveling piles (i.e., diving board 
shafts). The casing sizes and rotary drill sizes for each shaft are 
specified in Table 1.
    The large concrete monolithic sections used to create the dry docks 
and the center wall separation will be placed using a gantry crane. The 
gantry crane system will be structurally supported by the installation 
of 16 72-inch diameter shafts installed along the western extent of the 
Berth 1 face. The shafts will be installed using a DTH cluster drill as 
described for the temporary work trestle piles. The casing sizes and 
rotary drill sizes for the gantry crane support shafts are specified in 
Table 1.

P-310 Emergency Repairs

    Testing of the super flood basin on January 5, 2022 resulted in 
excess exfiltration through Berths 1 and 2, prompting the need for 
emergency repairs along Berth 1 as well as between the super flood 
basin entrance structure and the west closure wall. Emergency repairs 
consisted of the installation of sheet piles and the tremie pouring of 
concrete to fill in gaps along the structure walls and floor. 
Installation of emergency repairs at Berth 1 and the installation and 
removal of emergency repairs at the west closure wall and entrance 
structure occurred before the period described in the Navy's LOA 
application. Only the removal of Berth 1 emergency repair components 
will occur during the requested LOA period.
    The removal of the 216 28-inch wide, Z-shaped sheet piles along the 
Berth 1 face will be completed through direct pulling via barge-mounted 
crane or by vibratory hammer. Specific methods will be determined by 
the contractor based on resistance to extraction from the seabed. 
Direct pulling via crane is not anticipated to generate harmful levels 
of underwater sound. If required, the use of the vibratory hammer to 
extract the installed sheet piles will be limited to an initial effort 
to break the sheets loose, allowing them to be directly pulled out. As 
a conservative measure, vibratory extraction of these sheet piles is 
assumed for all analyses.
    The removal of 765 cubic meters (1,000 cy) of tremie concrete is 
anticipated to require use of a hydraulic rock hammer to break up 
material into smaller pieces. Smaller pieces will then be retrieved via 
excavator bucket for offsite disposal. The Navy estimates daily active 
use of the rock hammer for the removal of concrete from emergency 
repairs to be 4 hours per day.

[[Page 19511]]

Means and Methods for Noise Producing Activities

    Only 28-inch wide, Z-shaped sheet piles will be installed or 
removed with pile-driving equipment during P-381 construction. The 
installation of 28-inch wide, Z-shaped steel sheet piles will be 
installed initially using vibratory means and then finished with impact 
hammers, if necessary. Impact hammers will also be used to push 
obstructions out of the way and where sediment conditions do not permit 
the efficient use of vibratory hammers. Pile removal activities will 
use cranes and vibratory hammers exclusively.
    The removal of bedrock and concrete and the demolition of concrete 
shutter panels at Berth 11 and granite blocks and sheet piles at Berth 
1 during P-381 construction will be by mechanical means. These features 
will be demolished using a hydraulic rock hammer (i.e., hoe ram). The 
type/size of rock hammers used will be determined by the contractor 
selected to perform the work.
    Two methods of rock excavation will be used during P-381 
construction; DTH excavation and rotary drilling. During P-381 
construction, rotary drilling will be used to set the casings and pre-
drill rock sockets for DTH cluster drills. DTH excavation using mono-
hammers will be used to create shafts for rock anchors and tie downs 
and for the excavation of relief holes during mechanical bedrock 
removal. For the largest shafts (greater than 42-inches in diameter), 
DTH excavation will use a cluster drill. A cluster drill uses multiple 
mono-hammers within a single bit to efficiently break up bedrock and 
create large diameter holes (see Figure 1-5 in the Navy's application).

Concurrent Activities

    In order to maintain project schedules, it is likely that multiple 
pieces of equipment will operate at the same time within the basin. No 
ancillary activities are anticipated during the construction period 
that will require unimpeded access to the super flood basin. Therefore, 
it is anticipated that there will be space available within the project 
area for additional construction equipment. A maximum of 13 pieces of 
equipment could potentially operate in the project area at a single 
time. While this is an unlikely scenario, it could occur for a very 
brief period. Construction equipment will be staged along the perimeter 
of the super flood basin (Berth 11, Berth 1 and head wall) as well on 
multiple barges within the super flood basin. Table 2 provides a 
summary of possible equipment combinations that could be used 
simultaneously over the course of the construction period.

                                Table 2--Summary of Multiple Equipment Scenarios
----------------------------------------------------------------------------------------------------------------
                  Year                      Quantity                            Equipment
----------------------------------------------------------------------------------------------------------------
2023...................................               5  Rock Hammer (2), Vibratory Hammer (2), Impact Hammer
                                                          (1).
                                                      5  Rock Hammer (2), Vibratory Hammer (1), Impact Hammer
                                                          (1), DTH Mono-hammer (1).
                                                      5  Rock Hammer (1), Vibratory Hammer (1), Impact Hammer
                                                          (1), DTH Mono-hammer (1), Rotary Drill (1).
                                                      5  Rock Hammer (1), Vibratory Hammer (1), DTH Mono-hammer
                                                          (1), Cluster Drill (2).
                                                      5  Cluster Drill (2), Vibratory Hammer (1), Mono-hammer
                                                          DTH (1), Rotary Drill (1).
                                                      5  Rock Hammer (1), Impact Hammer (1), DTH Mono-hammer
                                                          (1), Cluster Drill (2).
                                                      6  Rock Hammer (2), DTH Mono-hammer (2), Cluster Drill
                                                          (1), Rotary Drill (1).
                                                      6  Rock Hammer (2), Vibratory Hammer (1), DTH Mono-hammer
                                                          (1), Rotary Drill (2).
                                                      8  Rock Hammer (2), Vibratory Hammer (2), DTH Mono-hammer
                                                          (2), Cluster Drill (2).
                                                     10  Rock Hammer (3), Vibratory Hammer (2), Impact hammer
                                                          (1), DTH Mono-hammer (2), Cluster Drill (2).
                                                     13  Rock Hammer (5), Cluster Drill (2), Vibratory Hammer
                                                          (2), Impact Hammer (1), Mono-hammer DTH (3).
2024...................................               8  Rock Hammer (2), Vibratory Hammer (2), DTH Mono-hammer
                                                          (2), Cluster Drill (2).
                                                      5  Cluster Drill (2), DTH mono-hammer (1), Vibratory
                                                          hammer (1), Impact Hammer (1).
                                                      3  Cluster Drill (2), DTH mono-hammer (1).
                                                      3  Cluster Drill (1), Rotary Drill (1), DTH mono-hammer
                                                          (1).
                                                      3  Rotary Drill (2), DTH mono-hammer (1).
2025...................................               3  Cluster Drill (2), DTH mono-hammer (1).
                                                      3  Cluster Drill (1), Rotary Drill (1), DTH mono-hammer
                                                          (1).
                                                      3  Rotary Drill (2), DTH mono-hammer (1).
                                                      2  Rotary Drill (2).
                                                      2  Cluster Drill (2).
----------------------------------------------------------------------------------------------------------------
Source: 381 Constructors, 2022.

    Mitigation, monitoring, and reporting measures are described in 
detail later in this document (please see Mitigation and Monitoring and 
Reporting).

Comments and Responses

    A notice of NMFS' proposed rulemaking to the Navy was published in 
the Federal Register on January 18, 2023 (88 FR 3146). That proposed 
rule described, in detail, the Navy's activities, the marine mammal 
species that may be affected by the activities, and the anticipated 
effects on marine mammals. In that proposed rule, we requested public 
input on the request for authorization described therein, our analyses, 
the proposed authorization, and any other aspect of the notice of 
proposed rulemaking, and requested that interested persons submit 
relevant information, suggestions, and comments. This proposed rule was 
available for a 30-day public comment period.
    During the 30-day public comment period, NMFS received no comments.

Changes From the Proposed IHA to Final IHA

    No public comments were received during the comment period; 
however, NMFS made a few minor clarifications and corrections in this 
final rule. In the sections of the documents that refer to the use of a 
bubble curtain, it was established that the bubble curtain will be used 
in cases where the Level A harassment zone extends to the full region 
of influence (ROI). To clarify this further, NMFS adds that this refers 
to all rock hammering and DTH cluster drilling. In addition, for bubble 
curtains, NMFS clarified that the air flow to the bubblers will be 
balanced across the entrance openings to the super flood basin, rather 
than the piles. Finally, NMFS removed the mitigation condition 
requiring that protected species observers (PSOs) work in shifts 
lasting no longer than 4 hours (hrs) with at least

[[Page 19512]]

a 1-hr break between shifts and limiting PSO duties to no more than 12 
hrs in a 24-hr period. This is not a required condition for the Navy 
for these construction activities, rather it is related to other 
activity types, such as offshore seismic surveys, but was accidentally 
included. That said, NMFS communicated to the Navy that observers 
should be given adequate breaks and work in shifts to reduce observer 
fatigue to ensure their ability to best monitor for marine mammals.

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. NMFS 
fully considered all of this information, and we refer the reader to 
these descriptions, referenced here, instead of reprinting the 
information. Additional information regarding population trends and 
threats may be found in NMFS' Stock Assessment Reports (SARs; 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS' 
website (https://www.fisheries.noaa.gov/find-species).
    Table 3 lists all species or stocks for which take is expected and 
authorized for this activity, and summarizes information related to the 
population or stock, including regulatory status under the MMPA and 
Endangered Species Act (ESA) and potential biological removal (PBR), 
where known. 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 
serious injury or mortality is expected to occur, PBR and annual 
serious injury and mortality from anthropogenic sources are included 
here as gross indicators of the status of the species or stocks 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' 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 stocks managed under the MMPA in this region 
are assessed in NMFS' U.S. Atlantic and Gulf of Mexico SARs. All values 
presented in Table 3 are the most recent available at the time of 
publication (including from the 2022 draft SARs) and are available 
online at: www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments).

                                              Table 3--Species Likely Impacted by the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                            Stock abundance Nbest,
                                                                                         ESA/MMPA status;   (CV, Nmin, most recent             Annual M/
             Common name                  Scientific name             MMPA stock          strategic (Y/N)    abundance survey) \2\     PBR       SI \3\
                                                                                                \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                 Order Cetartiodactyla--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocoenidae (porpoises):
    Harbor Porpoise.................  Phocoena...............  Gulf of Maine/Bay of     -; N                95,543 (0.31; 74,034;         851        164
                                                                Fundy.                                       2016).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
    Harbor seal.....................  Phoca vitulina.........  Western North Atlantic.  -; N                61,336 (0.08, 57,637;       1,729        339
                                                                                                             2018).
    Gray seal.......................  Halichoerus grypus.....  Western North Atlantic.  -; N                27,300 \4\ (0.22;           1,389      4,453
                                                                                                             22,785; 2016).
    Harp seal.......................  Pagophilus               Western North Atlantic.  -; N                7,600,000                 426,000    178,573
                                       groenlandicus.                                                        (unk,7,100.000, 2019).
    Hooded seal.....................  Cystophora cristata....  Western North Atlantic.  -; N                593,500...............    Unknown      1,680
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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-assessments assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable (N.A.).
\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\ This abundance value and the associated PBR value reflect the US population only. Estimated abundance for the entire Western North Atlantic stock,
  including animals in Canada, is 451,600. The annual M/SI estimate is for the entire stock.

    As indicated above, all five species (with five managed stocks) in 
Table 3 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur.
    A detailed description of the species likely to be affected by the 
Navy's construction activities, including brief introductions to the 
species and relevant stocks as well as available information regarding 
population trends and threats, and information regarding local 
occurrence, were provided in the Federal Register notice for the 
proposed rule (88 FR 3146, January 18, 2023). Since that time, we are 
not aware of any changes in the status of these species and stocks; 
therefore, detailed descriptions are not provided here. Please refer to 
that Federal Register notice for these descriptions. Please also refer 
to the NMFS website (https://www.fisheries.noaa.gov/find-species) for 
generalized species accounts.

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. Not all marine mammal species have equal 
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and 
Ketten, 1999; Au and Hastings,

[[Page 19513]]

2008). To reflect this, Southall et al. (2007, 2019) recommended that 
marine mammals be divided into hearing groups based on directly 
measured (behavioral or auditory evoked potential techniques) or 
estimated hearing ranges (behavioral response data, anatomical 
modeling, etc.). Note that no direct measurements of hearing ability 
have been successfully completed for mysticetes (i.e., low-frequency 
cetaceans). Subsequently, NMFS (2018a) 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 4.

                  Table 4--Marine Mammal Hearing Groups
                              [NMFS, 2018a]
------------------------------------------------------------------------
            Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen   7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans           150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans (true    275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 Cephalorhynchid, Lagenorhynchus
 cruciger & L. australis).
Phocid pinnipeds (PW) (underwater)     50 Hz to 86 kHz.
 (true seals).
Otariid pinnipeds (OW) (underwater)    60 Hz to 39 kHz.
 (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).

    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 (2018a) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    The effects of underwater noise from the Navy's construction 
activities have the potential to result in behavioral harassment of 
marine mammals in the vicinity of the project area. The notice of the 
proposed rulemaking (88 FR 3146, January 18, 2023) included a 
discussion of the effects of anthropogenic noise on marine mammals and 
the potential effects of underwater noise from the Navy's construction 
activities on marine mammals and their habitat. That information and 
analysis is referenced in this final rule and is not repeated here; 
please refer to the notice of the proposed rulemaking (88 FR 3146, 
January 18, 2023).

Estimated Take

    This section provides an estimate of the number of incidental takes 
authorized under the rule, which will inform both NMFS' consideration 
of ``small numbers'' and NMFS' negligible impact determinations.
    As described previously, no serious injury or mortality is 
anticipated or authorized for this activity. 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 will primarily be by Level B harassment, as use of 
the acoustic sources (i.e., impact and vibratory pile installation and 
removal, rotary drilling, DTH, and rock hammering) 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 high frequency species and/or 
phocids because predicted auditory injury zones are larger than for 
mid-frequency species and/or otariids. The requirements pertaining to 
mitigation and monitoring are expected to minimize the severity of the 
taking to the extent practicable. Below we describe how the authorized 
take numbers are estimated.
    For acoustic impacts, generally speaking, we estimate take by 
considering: (1) acoustic thresholds above which NMFS believes the best 
available science indicates marine mammals will be behaviorally 
harassed 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) the number of days of activities. We note 
that while these factors can contribute to a basic calculation to 
provide an initial prediction of potential 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 estimated take numbers.

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 be behaviorally harassed (equated to 
Level B harassment) or to incur PTS of some degree (equated to Level A 
harassment).
    Level B Harassment--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 or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source), the environment (e.g., bathymetry, other noises in the area, 
predators in the area), and the receiving animals (hearing, motivation, 
experience, demography, life stage, depth) and can be difficult to 
predict

[[Page 19514]]

(e.g., Southall et al., 2007, 2021; Ellison et al., 2012). Based on 
what the available science indicates and the practical need to use a 
threshold based on a metric that is both predictable and measurable for 
most activities, NMFS typically uses a generalized acoustic threshold 
based on received level to estimate the onset of behavioral harassment. 
NMFS generally predicts that marine mammals are likely to be 
behaviorally harassed in a manner considered to be Level B harassment 
when exposed to underwater anthropogenic noise above root-mean-squared 
pressure received levels (RMS SPL) of 120 dB (referenced to 1 
micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile-
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g., 
scientific sonar) sources. Generally speaking, Level B harassment take 
estimates based on these behavioral harassment thresholds are expected 
to include any likely takes by TTS as, in most cases, the likelihood of 
TTS occurs at distances from the source less than those at which 
behavioral harassment is likely. TTS of a sufficient degree can 
manifest as behavioral harassment, as reduced hearing sensitivity and 
the potential reduced opportunities to detect important signals 
(conspecific communication, predators, prey) may result in changes in 
behavior patterns that would not otherwise occur.
    The Navy's activities include the use of continuous (vibratory pile 
driving/removal, rotary drilling) and intermittent (impact pile 
driving, rock hammering) sources, and therefore the RMS SPL thresholds 
of 120 and 160 dB re 1 [mu]Pa, respectively, are applicable. DTH 
systems have both continuous and intermittent components as discussed 
in the Description of Sound Sources section in the proposed rule (88 FR 
3146, January 18, 2023). When evaluating Level B harassment, NMFS 
recommends treating DTH as a continuous source and applying the RMS SPL 
thresholds of 120 dB re 1 [mu]Pa (see NMFS recommended guidance on DTH 
systems at https://media.fisheries.noaa.gov/2022-11/PUBLIC%20DTH%20Basic%20Guidance_November%202022.pdf; NMFS, 2022).
    Level A harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0) 
(NMFS, 2018a) 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). The Navy's activities include 
the use of impulsive (impact pile driving, rock hammering, DTH) and 
non-impulsive (vibratory pile driving/removal, rotary drilling, DTH) 
sources.
    These thresholds are provided in the table 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: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 5--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.
Note: Peak sound pressure (Lpk) has a reference value of 1 [mu]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 are used in estimating the area ensonified above the 
acoustic thresholds, including 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., impact pile driving, vibratory pile 
driving, vibratory pile removal, rotary drilling, rock hammering, and 
DTH).
    Sound Source Levels--The intensity of pile driving sounds is 
greatly influenced by factors such as the type of piles, hammers, and 
the physical environment (e.g., sediment type) in which the activity 
takes place. The Navy evaluated sound source level (SL) measurements 
available for certain pile types and sizes from similar environments 
from other Navy pile driving projects, including from past projects 
conducted at the Shipyard, and used them as proxy SLs to determine 
reasonable SLs likely to result from the pile driving and drilling 
activities in their application. Projects reviewed were those most 
similar to the specified activity in terms of drilling and rock 
hammering activities, type and size of piles installed, method of pile 
installation, and substrate conditions. Some of the proxy source levels 
used are expected to be more conservative as compared to what may be 
realized by the actual pile driving to take place, as the values are 
from larger pile sizes. In some instances, for reasons described below, 
NMFS relied on alternative proxy SLs in our evaluation of the impacts 
of the Navy's activities on marine mammals (Table 6). Note that the 
source levels in Table 6 represent the SPL referenced at a distance of 
10 m from the source.

[[Page 19515]]



                      Table 6--Summary of Unattenuated In-Water Pile Driving Source Levels
----------------------------------------------------------------------------------------------------------------
                                                                                                       SELss (dB
                                 Installation                      Peak SPL      RMS SPL (dB re 1        re 1
          Pile type                 method         Pile diameter   (dB re 1          [mu]Pa)           [mu]Pa\2\
                                                                    [mu]Pa)                              sec)
----------------------------------------------------------------------------------------------------------------
Casing/Socket................  Rotary Drill....  126-inch........  NA......  154 (169 at 1 m).......  NA
                                                 102-inch........  NA......  154 (169 at 1 m).......  NA
                                                 84-inch.........  NA......  154 (169 at 1 m).......  NA
Shaft........................  DTH Cluster       108-inch........  NA......  201.6 \5\ (Level A)....  NA
                                Drill.                                       174 \6\ (Level B)......
                                                 84-inch.........  NA......  196.7 \5\ (Level A)....  NA
                                                                             174 \6\(Level B).......
                                                 78-inch.........  NA......  195.2 \5\ (Level A)....  181
                                                                             174 \6\ (Level B)......
                                                 72-inch.........  NA......  193.7 \5\ (Level A)....  NA
                                                                             174 \6\ (Level B)......
Rock anchor..................  DTH mono-hammer.  9-inch..........  172.....  167....................  146
Relief hole..................  DTH mono-hammer.  4 to 6-inch.....  170.....  \6\ 156................  144
Z-shaped Sheet...............  Impact..........  \1\ 28-inch.....  211.....  196....................  181
                               Vibratory.......  28-inch \2\.....  NA......  167....................  167
                               Vibratory.......  25-inch \3\.....  NA......  167....................  167
Bedrock and concrete           Rock Hammer \4\.  NA..............  197.....  186 \4\................  \4\ 171
 demolition.
----------------------------------------------------------------------------------------------------------------
\1\ An appropriate proxy value for impact driving 28-inch wide, Z-shaped sheet piles is not available, so a
  value for 30-inch steel pipe piles was used as a proxy value (NAVFAC SW, 2020 [p. A-4]).
\2\ An appropriate proxy value for vibratory pile driving 28-inch wide, Z-shaped sheet piles is not available,
  so a value for 30-inch steel pipe piles was used as a proxy value (Navy, 2015 [p. 14]).
\3\ An appropriate proxy value for vibratory pile driving 25-inch sheet piles is not available, so the value for
  28-inch wide, Z-shaped sheet piles was used as a proxy.
\4\ Escude, 2012.
\5\ RMS SPL values were derived from regression and extrapolation calculations of existing data by NMFS.
\6\SPLs vary from those proposed in the Navy's application as the NMFS DTH recommended guidance updated the
  source level proxy it recommends for some DTH systems after the Navy's application was deemed adequate and
  complete (NMFS, 2022).
Notes: All SPLs are unattenuated and represent the SPL referenced at a distance of 10 m from the source; NA =
  Not applicable; single strike SEL are the proxy source levels for impact pile driving used to calculate
  distances to PTS; dB re 1 [mu]Pa = decibels (dB) referenced to a pressure of 1 microPascal, measures
  underwater SPL.; dB re 1 [mu]Pa\2\-sec = dB referenced to a pressure of 1 microPascal squared per second,
  measures underwater SEL.

    With regards to the proxy values summarized in Table 6, very little 
information is available regarding source levels for in-water rotary 
drilling activities. As a conservative measure and to be consistent 
with previously issued IHAs for similar projects in the region, a proxy 
of 154 dB RMS is used for all rotary drilling activities (Dazey, 2012).
    NMFS recommends treating DTH systems as both impulsive and 
continuous, non-impulsive sound source types simultaneously. Thus, 
impulsive thresholds are used to evaluate Level A harassment, and the 
continuous threshold is used to evaluate Level B harassment. The Navy 
consulted with NMFS to obtain the appropriate proxy values for DTH 
mono- and cluster-hammers. With regards to DTH mono-hammers, NMFS 
recommended proxy levels for Level A harassment based on available data 
regarding DTH systems of similar sized piles and holes (Table 6) (Denes 
et al., 2019; Guan and Miner, 2020; Reyff and Heyvaert, 2019; Reyff, 
2020; Heyvaert and Reyff, 2021). No hydroacoustic data exist for 
cluster DTH systems; therefore, NMFS recommends proxy values based off 
of regression and extrapolation calculations of existing data for mono-
hammers until hydroacoustic data on DTH cluster drills be obtained 
(NMFS, 2022). Because of the high number of hammers and strikes for 
this system, DTH cluster drills are treated as a continuous sound 
source for the time component of Level A harassment (i.e., for the 
entire duration DTH cluster drills are operational, they are considered 
to be producing strikes, rather than indicating the number of strikes 
per second, which is unknown), but still used the impulsive thresholds.
    At the time of the Navy's application submission, NMFS recommended 
that the RMS SPL at 10 m should be 167 dB when evaluating Level B 
harassment (Heyvaert and Reyff, 2021 as cited in NMFS, 2021b) for all 
DTH pile/hole sizes. However, since that time, NMFS has received 
additional clarifying information regarding DTH data presented in Reyff 
and Heyvaert (2019) and Reyff (2020) that allows for different RMS SPL 
at 10 m to be recommended for piles/holes of varying diameters (NMFS, 
2022). Therefore, the following proxy RMS SPLs at 10 m are used to 
evaluate Level B harassment from this sound source in this analysis 
(Table 6): 156 dB RMS for the 4 to 6 inch mono hammers (Reyff and 
Heyvaert, 2019; Reyff, 2020), 167 dB RMS for the 9 inch mono-hammers 
(Heyvaert and Reyff, 2021), and 174 dB RMS for all DTH cluster drills 
greater or equal to 74 inches (Reyff and Heyvaert, 2019; Reyff, 2020). 
See Footnote 6 in Table 6.
    Rock hammering is analyzed as an impulsive noise source. For 
purposes of this analysis, it is assumed that the hammer will have a 
maximum strike rate of 460 strikes per minute and will operate for a 
maximum duration of 15 minutes before needing to reposition or stop to 
check progress. Therefore, noise impacts for rock hammering activities 
are assessed using the number of blows per 15-minute interval (6,900 
blows) and the number of 15-minute intervals anticipated over the 
course of the day based on the durations provided in Tables 1, 7, and 
8. As with rotary drilling, very little information is available 
regarding source levels associated with nearshore rock hammering. In 
previous IHAs related to the Shipyard, NMFS relied on preliminary 
measurements from the Tappan Zee Bridge replacement project (Reyff, 
2018a, 2018b) as well as data from a WSDOT concrete pier demolition 
project (Escude, 2012) to inform proxy SLs for rock hammering. However, 
a few discrepancies in the preliminary data of the Tappan Zee Bridge 
reports have been identified resulting from NMFS' further inspection 
into the report's data. Therefore, the SLs reported only from the 
Escude (2012) concrete pier demolition project are used as proxy values 
for rock hammering activities associated with P-381 (Table 6).
    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

[[Page 19516]]

bottom composition and topography. The general formula for underwater 
TL is:

TL = B * log10 (R1/R2),

Where:

B = transmission loss coefficient (assumed to be 15)
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement.

    This formula neglects loss due to scattering and absorption, which 
is assumed to be zero here. The degree to which underwater sound 
propagates away from a sound source is dependent on a variety of 
factors, most notably the water bathymetry and presence or absence of 
reflective or absorptive conditions including in-water structures and 
sediments. 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 
appropriate assumption for the Navy's activities in the absence of 
specific modelling. All Level B harassment isopleths are reported in 
Tables 7 and 8 considering RMS SLs.
    Level A Harassment Zones--The ensonified area associated with Level 
A harassment is more technically challenging to predict due to the need 
to account for a duration component. Therefore, NMFS developed an 
optional User Spreadsheet tool to accompany the Technical Guidance 
(NMFS, 2018a) that can be used to relatively simply predict an isopleth 
distance for use in conjunction with marine mammal density or 
occurrence to help predict potential takes. We note that because of 
some of the assumptions included in the methods underlying this 
optional tool, we anticipate that the resulting isopleth estimates are 
typically going to be overestimates of some degree, which may result in 
an overestimate of potential take by Level A harassment. However, this 
optional tool offers the best way to estimate isopleth distances when 
more sophisticated modeling methods are not available or practical. For 
stationary sources (such as from impact and vibratory pile driving, 
drilling, DTH, and rock hammering), the optional User Spreadsheet tool 
predicts the distance at which, if a marine mammal remained at that 
distance for the duration of the activity, it would be expected to 
incur PTS. Inputs used in the User Spreadsheet can be found in Appendix 
A of the Navy's application, Appendix A of the Navy's addendum, and the 
resulting isopleths are reported in Tables 7 and 8.

                              Table 7--Calculated Distance and Areas of Level A and Level B Harassment for Impulsive Noise
                                                  [DTH, impact pile driving, hydraulic rock hammering]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                    Level A harassment \2\            Level B harassment
                                                                                  Total   --------------------------------------------------------------
 Activity ID     Year \1\/activity         Purpose          Duration, count,   production     High frequency
                                                           size, and or rate      days      cetaceans (harbor     Phocid pinnipeds       All species
                                                                                                porpoise)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1............  2 Hydraulic Rock      Shutter Panel        5 hours/day (20              56  5,034.5 m/0.417417   2,261.9 m/0.417417   541.17 m/0.277858
                Hammer.               Demolition (112      intervals/day at                 km\2\.               km\2\.               km\2\.
                                      panels).             15 each).
3............  2-3 Hydraulic Rock    Removal of Granite   2.5 hours/day (10            47  3,171.6 m/0.417417   1,424.9 m/0.417417   541.17 m/0.277858
                Hammer.               Quay Wall (2,800     intervals/day at                 km\2\.               km\2\.               km\2\.
                                      cy).                 15 min each).
4............  2-3 Hydraulic Rock    Berth 1 Top of Wall  10 hours/day (40             74  7,991.8 m/0.417417   3,590.5 m/0.417417   541.17 m/0.277858
                Hammer.               Demolition for       intervals/day at                 km\2\.               km\2\.               km\2\.
                                      Waler Install (320   15 min each).
                                      lf).
6............  2 Hydraulic Rock      Mechanical Rock      12 hours/day (48             60  9,024.7 m/0.417417   4,054.5 m/0.417417   541.17 m/0.277858
                Hammer.               Removal (700 cy)     intervals/day at                 km\2\.               km\2\.               km\2\.
                                      at Berth 11 Basin    15 min each).
                                      Floor.
10...........  2 Hydraulic Rock      Mechanical Rock      12 hours/day (48             25  9,024.7 m/0.417417   4,054.5 m/0.417417   541.17 m/0.277858
                Hammer.               Removal (300 cy)     intervals/day at                 km\2\.               km\2\.               km\2\.
                                      at Berth 1 Basin     15 min each).
                                      Floor.
21...........  2 Hydraulic Rock      Removal of           4 hours/day (16              15  4,388.6 m/0.417417   1,949.2 m/0.417417   541.17 m/0.277858
                Hammer.               Emergency Repair     intervals/day at                 km\2\.               km\2\.               km\2\.
                                      Concrete (500 cy)    15 min each).
                                      at Berth 1.
7............  2 DTH Mono-hammer...  Relief Holes at      924 4-6 inch holes           35  178.9 m/0.047675     80.4 m/0.014413      2,512 m/0. 417417
                                      Berth 11 Basin       27 holes/day.                    km\2\.               km\2\.               km\2\.
                                      Floor.
11...........  2 DTH Mono-hammer...  Dry Dock 1 North     50 9-inch holes 2            25  244.8 m/0.073751     110 m/0.022912       13,594 m/0.417417
                                      entrance Rock        holes/day.                       km\2\.               km\2\.               km\2\.
                                      Anchors.
22...........  2-3 DTH Mono-hammer.  Center Wall          72 9-inch holes 2            36  244.8 m/0.073751     110 m/0.022912       13,594 m/0.417417
                                      Foundation Rock      holes/day.                       km\2\.               km\2\.               km\2\.
                                      Anchors.
34...........  3-4 DTH Mono-hammer.  Dry Dock 1 North     36 9-inch holes 2            18  244.8 m/0.073751     110 m/0.022912       13,594 m/0.417417
                                      Rock Anchors.        holes/day.                       km\2\.               km\2\.               km\2\.
35...........  4-5 DTH Mono-hammer.  Dry Dock 1 West      36 9-inch holes 2            18  244.8 m/0.073751     110 m/0.022912       13,594 m/0. 417417
                                      Rock Anchors.        holes/day.                       km\2\.               km\2\.               km\2\.
R............  2 Impact Pile         Dry Dock 1 North     48 28-inch Z-shaped           6  1,568.6 m/0.417417   704.7 m/0.364953     2,512 m/0.417417
                Driving.              Entrance Temporary   sheets 8 sheets/                 km\2\.               km\2\.               km\2\.
                                      Cofferdam.           day.
5............  2 Impact Pile         Berth 1 Support of   28 28-inch Z-shaped           8  988.2 m/0.403411     444.0 m/0.201158     2,512 m/0.417417
                Driving.              Excavation.          sheets 4 piles/day.              km\2\.               km\2\.               km\2\.
8............  2 Impact Pile         Temporary Cofferdam  14 28-inch Z-shaped           4  988.2 m/0.403411     444.0 m/0.201158     2,512 m/0.417417
                Driving.              Extension.           sheets 4 piles/day.              km\2\.               km\2\.               km\2\.

[[Page 19517]]

 
12...........  2 Impact Pile         Center Wall Tie-in   15 28-inch Z-shaped           4  988.2 m/0.403411     444.0 m/0.201158     2,512 m/0.417417
                Driving.              to West Closure      sheets 4 piles/day.              km\2\.               km\2\.               km\2\.
                                      Wall.
24...........  2-3 Impact Pile       Center Wall East     23 28-inch Z-shaped          12  622.5 m/0.334747     279.7 m/0.090757     2,512 m/0.417417
                Driving.              Tie-in to Existing   sheets 2 piles/day.              km\2\.               km\2\.               km\2\.
                                      Wall.
A4...........  2 DTH Cluster Drill.  Dry Dock 1 North     18 78-inch shafts           117  84,380.4 m/0.417417  37,909.7 m/0.417417  39,811 m/0.417417
                                      Entrance             10 hours/day 6.5                 km\2\.               km\2\.               km\2\.
                                      Foundation Support   days/shaft.
                                      Piles.
9d...........  2 DTH Cluster Drill.  Gantry Crane         16 72-inch shafts            80  67,025.7 m/0.417417  30,112.8 m/0.417417  39,811 m/0.417417
                                      Support Piles.       10 hours/day 5                   km\2\.               km\2\.               km\2\.
                                                           days/shaft.
13d..........  2-3 DTH Cluster       Dry Dock 1 North     20 84-inch shafts            70  106,228.6 m/         47,725.5 m/0.417417  39,811 m/0.417417
                Drill.                Temporary Work       10 hours/day 3.5                 0.417417 km\2\.      km\2\.               km\2\.
                                      Trestle.             days/shaft.
15d..........  2-3 DTH Cluster       Dry Dock 1 North     18 78-inch shafts           135  84,380.4 m/0.417417  37,909.7 m/0.417417  39,811 m/0.417417
                Drill.                Leveling Piles       10 hours/day 7.5                 km\2\.               km\2\.               km\2\.
                                      (Diving Board        days/shaft.
                                      Shafts).
16d..........  2-3 DTH Cluster       Wall Shafts for Dry  20 78-inch shafts           150  84,380.4 m/0.417417  37,909.7 m/0.417417  39,811 m/0.417417
                Drill.                Dock 1 North.        10 hours/day 7.5                 km\2\.               km\2\.               km\2\.
                                                           days/shaft.
17d..........  2-3 DTH Cluster       Foundation Shafts    23 108-inch shafts          196  225,376.2 m/         101,255.2 m/         39,811 m/0.417417
                Drill.                for Dry Dock 1       10 hours/day 8.5                 0.417417 km\2\.      0.417417 km\2\.      km\2\.
                                      North.               days/shaft.
29d..........  3-4 DTH Cluster       Dry Dock 1 West      20 84-inch shafts            70  106,228.6 m/         47,725.5 m/0.417417  39,811 m/0.417417
                Drill.                Temporary Work       10 hours/day 3.5                 0.417417 km\2\.      km\2\.               km\2\.
                                      Trestle.             days/shaft.
31d..........  3-4 DTH Cluster       Wall Shafts for Dry  22 78-inch shafts           165  84,380.4 m/0.417417  37,909.7 m/0.417417  39,811 m/0.417417
                Drill.                Dock 1 West.         10 hours/day 7.5                 km\2\.               km\2\.               km\2\.
                                                           days/shaft.
32d..........  3-4 DTH Cluster       Foundation Shafts    23 108-inch shafts          196  225,376.2 m/         101,255.2 m/         39,811 m/0.417417
                Drill.                for Dry Dock 1       10 hours/day 8.5                 0.417417 km\2\.      0.417417 km\2\.      km\2\.
                                      West.                days/pile.
33d..........  3-4 DTH Cluster       Dry Dock 1 West      18 78-inch shafts           135  84,380.4 m/0.417417  37,909.7 m/0.417417  39,811 m/0.417417
                Drill.                Leveling Piles       10 hours/day 7.5                 km\2\.               km\2\.               km\2\.
                                      (Diving Board        days/pile.
                                      Shafts).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Note, for the purposes of this analysis, the construction years are identified as years 2 through 5; takes for marine mammals during Year 1 of the
  Navy's construction activities were authorized in a previously issued IHA (87 FR 19886, April 6, 2022).
\2\ To determine underwater harassment zone size, ensonified areas from the source were clipped along the shoreline using Geographical Information
  Systems (GIS).


                            Table 8--Calculated Distance and Areas of Level A and Level B Harassment for Non-Impulsive Noise
                                                 [Rotary drilling and vibratory pile driving/extracting]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                          Level A harassment \2\                  Level B harassment
                                               Duration, count,     Total   ----------------------------------------------------------------------------
 Activity      Year \1\/          Purpose        size, and or    production       High frequency
    ID         activity                              rate           days        cetaceans (harbor        Phocid pinnipeds             All species
                                                                                    porpoise)
--------------------------------------------------------------------------------------------------------------------------------------------------------
R........  2 Vibratory Pile  Dry Dock 1 North  48 28-inch Z-              6  19.4 m/0.001041 km\2\    8.0 m/0.0002 km\2\      13,594 m/0.417417 km\2\.
            Driving.          Entrance          shaped sheets 8
                              Temporary         sheets/day.
                              Cofferdam.
2........  2-3 Vibratory     Remove Berth 1    168 25-inch Z-            42  12.2 m/0.000454 km\2\    5.0 m/0.000078 km\2\    13,594 m/0.417417 km\2\.
            Extraction.       Sheet Piles.      shaped sheets 4
                                                piles/day.
5........  2 Vibratory Pile  Install Berth 1   28 28-inch Z-              8  12.2 m/0.000454 km\2\    5.0 m/0.000078 km\2\    13,594 m/0.417417 km\2\.
            Driving.          Support of        shaped sheets 4
                              Excavation.       piles/day.
8........  2 Vibratory Pile  Install           14 28-inch Z-              4  12.2 m/0.000454 km\2\    5.0 m/0.000078 km\2\    13,594 m/0.417417 km\2\.
            Driving.          Temporary         shaped sheets 4
                              Cofferdam         piles/day.
                              Extension.
12.......  2 Vibratory Pile  Center Wall Tie-  15 28-inch Z-              4  12.2 m/0.000454 km\2\    5.0 m/0.000078 km\2\    13,594 m/0.417417 km\2\.
            Driving.          In to Existing    shaped sheets 4
                              West Closure      piles/day.
                              Wall.
18.......  2 Vibratory       Berth 11 End      60 28-inch Z-             10  19.4 m/0.001041 km\2\    8.0 m/0.0002 km\2\      13,594 m/0.417417 km\2\.
            Extraction.       Wall Temporary    shaped sheets 8
                              Guide Wall.       piles/day.
19.......  2 Vibratory       Remove Berth 1    28 28-inch Z-              5  19.4 m/0.001041 km\2\    8.0 m/0.0002 km\2\      13,594 m/0.417417 km\2\.
            Extraction.       Support of        shaped sheets 8
                              Excavation.       piles/day.
20.......  2 Vibratory       Remove Berth 1    108 28-inch Z-            18  16.0 m/0.000733 km\2\    6.6 m/0.000136 km\2\    13,594 m/0.417417 km\2\.
            Extraction.       Emergency         shaped sheets 6
                              Repairs.          piles/day.

[[Page 19518]]

 
23.......  2-3 Vibratory     Dry Dock 1 North- 16 28-inch Z-              3  19.4 m/0.001041 km\2\    8.0 m/0.0002 km\2\      13,594 m/0.417417 km\2\.
            Extraction.       Remove Center     shaped sheets 8
                              Wall Tie-in to    piles/day.
                              West Closure
                              Wall.
24.......  2-3 Vibratory     Center Wall East  23 28-inch Z-             12  7.7 m/0.000185 km\2\     3.2 m/0.000032 km\2\    13,594 m/0.417417 km\2\.
            Pile Driving.     Tie-in to         shaped sheets 2
                              Existing Wall.    piles/day.
25.......  2-3 Vibratory     Dry Dock 1 West   15 28-inch Z-              3  19.4 m/0.001041 km\2\    8.0 m/0.0002 km\2\      13,594 m/0.417417 km\2\.
            Extraction.       Remove Center     shaped sheets 8
                              Wall Tie-in to    piles/day.
                              West Closure
                              Wall.
26.......  2-3 Vibratory     Remove Center     23 28-inch Z-             12  19.4 m/0.001041 km\2\    8.0 m/0.0002 km\2\      13,594 m/0.417417 km\2\.
            Extraction.       Wall Tie-in to    shaped sheets 8
                              Existing Wall.    piles/day.
27.......  2-3 Vibratory     Remove Temporary  96 28-inch Z-             12  19.4 m/0.001041 km\2\    8.0 m/0.0002 km\2\      13,594 m/0.417417 km\2\.
            Extraction.       Cofferdam.        shaped sheets 8
                                                piles/day.
28.......  2-3 Vibratory     Remove Temporary  14 28-inch Z-              2  19.4 m/0.001041 km\2\    8.0 m/0.0002 km\2\      13,594 m/0.417417 km\2\.
            Extraction.       Cofferdam         shaped sheets 8
                              Extension.        piles/day.
A1.......  2 Rotary Drill..  Dry Dock 1 North  18 102-inch               18  2.1 m/0.000014 km\2\     1.3 m/0.000005 km\2\    1,848 m/0.417417 km\2\.
                              Entrance          borings 1 hour/
                              Foundation        day 1 casing/
                              Support Piles--   day.
                              Install Outer
                              Casing.
A2.......  2 Rotary Drill..  Dry Dock 1 North  18 102-inch               18  8.9 m/0.000248 km\2\     5.4 m/0.000091 km\2\    1,848 m/0.41747 km\2\.
                              Entrance          borings 9 hours/
                              Foundation        day 1 socket/
                              Support Piles--   day.
                              Pre-Drill
                              Socket.
A3.......  2 Rotary Drill..  Dry Dock 1 North  18 102-inch               18  0.8 m/0.000002 km\2\     0.5 m/0.000001 km\2\    1,848 m/0.417417 km\2\.
                              Entrance          borings 15
                              Foundation        minutes/casing
                              Support Piles--   1 casing/day.
                              Remove Outer
                              Casing.
9a.......  2 Rotary Drill..  Gantry Crane      16 102-inch               16  2.1 m/0.000014 km\2\     1.3 m/0.000005 km\2\    1,848 m/0.417417 km\2\.
                              Support--Instal   borings 1 hour/
                              l Outer Casing.   day 1 casing/
                                                day.
9b.......  2 Rotary Drill..  Gantry Crane      16 102-inch               16  8.9 m/0.000248 km\2\     5.4 m/0.000091 km\2\    1,848 m/0.417417 km\2\.
                              Support--Pre-     borings 9 hours/
                              Drill Socket.     day 1 socket/
                                                day.
9c.......  2 Rotary Drill..  Gantry Crane      16 102-inch               16  0.8 m/0.000002 km\2\     0.5 m/0.000001 km\2\    1,848 m/0.417417 km\2\.
                              Support--Remove   borings 15
                              Outer Casing.     minutes/casing
                                                1 casing/day.
13a......  2-3 Rotary Drill  Dry Dock 1 North  20 102-inch               20  2.1 m/0.000014 km\2\     1.3 m/0.000005 km\2\    1,848 m/0.417417 km\2\.
                              Temporary Work    borings 1 hour/
                              Trestle--Instal   day 1 casing/
                              l Outer Casing.   day.
13b......  2-3 Rotary Drill  Dry Dock 1 North  20 102-inch               20  8.9 m/0.000248 km\2\     5.4 m/0.000091 km\2\    1,848 m/0.417417 km\2\.
                              Temporary Work    borings 9 hours/
                              Trestle--Pre-     day 1 socket/
                              Drill Socket.     day.
13c......  2-3 Rotary Drill  Dry Dock 1 North  20 102-inch               20  0.8 m/0.000002 km\2\     0.5 m/0.000001 km\2\    1,848 m/0.417417 km\2\.
                              Temporary Work    borings 15
                              Trestle--Remove   minutes/casing
                              Outer Casing.     1 casing//day.
14.......  2-3 Rotary Drill  Remove Dry Dock   20 84-inch                20  0.8 m/0.000002 km\2\     0.5 m/0.000001 km\2\    1,848 m/0.417417 km\2\.
                              1 North           borings 15
                              Temporary Work    minutes/casing
                              Trestle Piles.    1 casing/day.
15a......  2-3 Rotary Drill  Dry Dock 1 North  18 84-inch                18  2.1 m/0.000014 km\2\     1.3 m/0.000005km\2\     1,848 m/0.417417 km\2\.
                              Leveling Piles--  borings 1 hour/
                              Install Outer     day 1 casing/
                              Casing.           day.
15b......  2-3 Rotary Drill  Dry Dock 1 North  18 84-inch                18  8.9 m/0.000248 km\2\     5.4 m/0.000091 km\2\    1,848 m/0.417417 km\2\.
                              Leveling Piles--  borings 9 hours/
                              Pre-Drill         day 1 socket/
                              Socket.           day.
15c......  2-3 Rotary Drill  Dry Dock 1 North  18 84-inch                18  0.8 m/0.000002 km\2\     0.5 m/0.000001 km\2\    1,848 m/0.417417 km\2\.
                              Leveling Piles--  borings 15
                              Remove Outer      minutes/casing
                              Casing.           1 casing/day.
16a......  2-3 Rotary Drill  Dry Dock 1 North  20 102-inch               20  2.1 m/0.000014 km\2\     1.3 m/0.000005 km\2\    1,848 m/0.417417 km\2\.
                              Wall Shafts--     borings 1 hour/
                              Install Outer     day 1 casing/
                              Casing.           day.
16b......  2-3 Rotary Drill  Dry Dock 1 North  20 102-inch               20  8.9 m/0.000248 km\2\     5.4 m/0.000091 km\2\    1,848 m/0.417417 km\2\.
                              Wall Shafts--     borings 9 hours/
                              Pre-Drill         day 1 socket/
                              Socket.           day.
16c......  2-3 Rotary Drill  Dry Dock 1 North  20 102-inch               20  0.8 m/0.000002 km\2\     0.5 m/0.000001 km\2\    1,848 m/0.417417 km\2\.
                              Wall Shafts--     borings 15
                              Remove Outer      minutes/casing
                              Casing.           1 casing/day.
17a......  2-3 Rotary Drill  Dry Dock 1 North  23 126-inch               23  2.1 m/0.000014 km\2\     1.3 m/0.000005 km\2\    1,848 m/0.417417 km\2\.
                              Foundation        borings 1 hour/
                              Shafts--Install   day 1 casing/
                              Outer Casing.     day.

[[Page 19519]]

 
17b......  2-3 Rotary Drill  Dry Dock 1 North  23 126-inch               23  8.9 m/0.000248 km\2\     5.4 m/0.000091 km\2\    1,848 m/0.417417 km\2\.
                              Foundation        borings 9 hours/
                              Shafts Pre-       day 1 socket/
                              Drill Sockets.    day.
17c......  2-3 Rotary Drill  Dry Dock 1 North  23 126-inch               23  0.8 m/0.000002 km\2\     0.5 m/0.000001 km\2\    1,848 m/0.417417 km\2\.
                              Foundation        borings 15
                              Shafts--Remove    minutes/casing
                              Outer Casing.     1 casing/day.
29a......  3-4 Rotary Drill  Dry Dock 1 West   20 102-inch               20  2.1 m/0.000014 km\2\     1.3 m/0.000005 km\2\    1,848 m/0.417417 km\2\.
                              Temporary Work    borings 1 hour/
                              Trestle--Instal   day 1 casing/
                              l Outer Casing.   day.
29b......  3-4 Rotary Drill  Dry Dock 1 West   20 102-inch               20  8.9 m/0.000248 km\2\     5.4 m/0.000091 km\2\    1,848 m/0.417417 km\2\.
                              Temporary Work    borings 9 hours/
                              Trestle--Pre-     day 1 socket/
                              Drill Socket.     day.
29c......  3-4 Rotary Drill  Dry Dock 1 West   20 102-inch               20  0.8 m/0.000002 km\2\     0.5 m/0.000001 km\2\    1,848 m/0.417417 km\2\.
                              Temporary Work    borings 15
                              Trestle--Remove   minutes/casing
                              Outer Casing.     1 casing/day.
30.......  3-4 Rotary Drill  Dry Dock 1 West   20 84-inch                20  0.8 m/0.000002 km\2\     0.5 m/0.000001 km\2\    1,848 m/0.417417 km\2\.
                              Remove            borings 15
                              Temporary Work    minutes/pile 1
                              Trestle Piles.    pile/day.
31a......  3-4 Rotary Drill  Dry Dock 1 West   22 102-inch               22  2.1 m/0.000014 km\2\     1.3 m/0.000005km\2\     1,848 m/0.417417 km\2\.
                              Wall Shafts--     borings 1 hour/
                              Install Outer     day 1 casing/
                              Casing.           day.
31b......  3-4 Rotary Drill  Dry Dock 1 West   22 102-inch               22  8.9 m/0.000248 km\2\     5.4 m/0.000091 km\2\    1,848 m/0.417417 km\2\.
                              Wall Shafts--     borings 9 hours/
                              Pre-Drill         day 1 socket/
                              Socket.           day.
31c......  3-4 Rotary Drill  Dry Dock 1 West   22 102-inch               22  0.8 m/0.000002 km\2\     0.5 m/0.000001 km\2\    1,848 m/0.417417 km\2\.
                              Wall Shafts--     borings 15
                              Remove Outer      minutes/casing
                              Casing.           1 casing/day.
32a......  3-4 Rotary Drill  Dry Dock 1 West   23 126-inch               23  2.1 m/0.000014 km\2\     1.3 m/0.000005 km\2\    1,848 m/0.417417 km\2\.
                              Foundation        borings 1 hour/
                              Shafts--Install   day 1 casing/
                              Outer Casing.     day.
32b......  3-4 Rotary Drill  Dry Dock 1 West   23 126-inch               23  8.9 m/0.000248 km\2\     5.4 m/0.000091 km\2\    1,848 m/0.417417 km\2\.
                              Foundation        borings 9 hours/
                              Shafts Pre-       day 1 socket/
                              Drill Sockets.    day.
32c......  3-4 Rotary Drill  Dry Dock 1 West   23 126-inch               23  0.8 m/0.000002 km\2\     0.5 m/0.000001 km\2\    1,848 m/0.417417 km\2\.
                              Foundation        borings 15
                              Shafts--Remove    minutes/casing
                              Outer Casing.     1 casing/day.
33a......  3-4 Rotary Drill  Dry Dock 1 North  18 84-inch                18  2.1 m/0.000014 km\2\     1.3 m/0.000005 km\2\    1,848 m/0.417417 km\2\.
                              Leveling Piles--  borings 1 hour/
                              Install Outer     day 1 casing/
                              Casing.           day.
33b......  3-4 Rotary Drill  Dry Dock 1 West   18 84-inch                18  8.9 m/0.000248 km\2\     5.4 m/0.000091 km\2\    1,848 m/0.417417 km\2\.
                              Leveling Piles--  borings 9 hours/
                              Pre-Drill         day 1 socket/
                              Socket.           day.
33c......  3-4 Rotary Drill  Dry Dock 1 North  18 84-inch                18  0.8 m/0.000002 km\2\     0.5 m/0.000001 km\2\    1,848 m/0.417417 km\2\.
                              Leveling Piles--  borings 15
                              Remove Outer      minutes/casing
                              Casing.           1 casing/day.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Note, for the purposes of this analysis, the construction years are identified as years 2 through 5; takes for marine mammals during Year 1 of the
  Navy's construction activities were authorized in a previously issued IHA (87 FR 19886, April 6, 2022).
\2\ To determine underwater harassment zone size, ensonified areas from the source were clipped along the shoreline using Geographical Information
  Systems (GIS).

    The calculated maximum distances corresponding to the underwater 
marine mammal harassment zones from impulsive (impact pile driving, 
rock hammering, DTH) and non-impulsive (vibratory pile driving, rotary 
drilling) noise and the area of the harassment zone within the ROI are 
summarized in Tables 7 and 8, respectively. Sound source locations were 
chosen to model the greatest possible affected areas; typically, these 
locations will be at the riverward end of the super flood basin. The 
calculated distances do not take the land masses into consideration, 
but the ensonified areas do. Neither consider the reduction that will 
be achieved by the required use of a bubble curtain and therefore all 
take estimates are considered conservative. Refer to Figures 6-1 
through 6-20 of the Navy's application for visual representations of 
the calculated maximum distances corresponding to the underwater marine 
mammal harassment zones from impulsive (impact pile driving, rock 
hammering, DTH) and non-impulsive (vibratory pile driving, rotary 
drilling) noise and the corresponding area of the harassment zone 
within the ROI.
    Calculated distances to Level A harassment and Level B harassment 
thresholds are large, especially for DTH and rock hammering activities. 
However, in most cases the full distance of sound propagation will not 
be reached due to the presence of land masses and anthropogenic 
structures that will prevent the noise from reaching nearly the full 
extent of the harassment isopleths. Refer to Figure 1-3 in the Navy's 
application for the ROI, which illustrates that the land masses 
preclude the sound from traveling more than approximately 870 m (3,000 
ft) from the source, at most. Areas encompassed within the threshold 
(harassment zones) were calculated by using a Geographical Information 
System (GIS) to clip the maximum calculated distances to the extent of 
the ROI (see Figure 2).

[[Page 19520]]

    Concurrent Activities--Simultaneous use of pile drivers, hammers, 
and drills could result in increased SPLs and harassment zone sizes 
given the proximity of the component sites and the rules of decibel 
addition (see Table 9 below). Due to the relatively small size of the 
ROI, the use of a single DTH cluster drill or rock hammer will ensonify 
the entire ROI to the Level A (PTS Onset) harassment thresholds (refer 
to Table 7). Therefore, when this equipment is operated in conjunction 
with other noise-generating equipment, there will be no change in the 
size of the harassment zone. The entire ROI will remain ensonified to 
the Level A harassment thresholds for the duration of the activity and 
there will be no Level B harassment zone. However, when DTH cluster 
drills or rock hammers are not in use, increased SPLs and harassment 
zone sizes within the ROI could result. Due to the substantial amount 
of rock hammering and DTH excavation required for the construction of 
the multifunctional expansion of Dry Dock 1, the only scenarios 
identified in which cluster drills and/or rock hammers will not be in 
operation will be at the end of the project (construction years 3 and 
4) when two rotary drills or two rotary drills and a DTH mono-hammer 
(9-inch) could be used simultaneously (refer to Table 2).
    When two noise sources have overlapping sound fields, there is 
potential for higher sound levels than for non-overlapping sources 
because the isopleth of one sound source encompasses the sound source 
of another isopleth. In such instances, the sources are considered 
additive and combined using the rules of decibel addition, presented in 
Table 9 below (NMFS, 2021d; WSDOT, 2020).

         Table 9--Adjustments for Sound Exposure Level Criterion
------------------------------------------------------------------------
                                                       Adjustments to
                                  Difference in      specifications for
         Source types            sound level (at     Level A harassment
                                specified meters)        RMS/SELss*
                                                        calculations
------------------------------------------------------------------------
Non-impulsive, continuous/Non-  0 or 1 dB........  Add 3 dB to the
 impulsive, continuous, OR                          highest sound level
                                                    (at specified
                                                    meters) AND adjust
                                                    number of piles per
                                                    day to account for
                                                    overlap (space and
                                                    time).
                                2 or 3 dB........  Add 2 dB to the
                                                    highest sound level
                                                    (at specified
                                                    meters) AND adjust
                                                    number of piles per
                                                    day to account for
                                                    overlap (space and
                                                    time).
Impulsive source (multiple      4 to 9 dB........  Add 1 dB to the
 strikes per second)/Impulsive                      highest sound level
 source (multiple strikes per                       (at specified
 second.                                            meters) AND adjust
                                                    number of piles per
                                                    day to account for
                                                    overlap (space and
                                                    time).
                                10 dB or more....  Add 0 dB to the
                                                    highest sound level
                                                    (at specified
                                                    meters) AND adjust
                                                    number of piles per
                                                    day to account for
                                                    overlap (space and
                                                    time).
------------------------------------------------------------------------
* RMS level for vibratory pile driving/rotary hammer and single strike
  SEL (SELss) level for DTH/rock hammer.

    For simultaneous usage of three or more continuous sound sources, 
the three overlapping sources with the highest SLs are identified. Of 
the three highest SLs, the lower two are combined using the above 
rules, then the combination of the lower two is combined with the 
highest of the three. For example, with overlapping isopleths from 24-, 
36-, and 42-inch diameter steel pipe piles with sound source levels of 
161, 167, and 168 dB RMS respectively, the 24- and 36-inch would be 
added together; given that 167-161 = 6 dB, then 1 dB is added to the 
highest of the two sound source levels (167 dB), for a combined noise 
level of 168 dB. Next, the newly calculated 168 dB is added to the 42-
inch steel pile with sound source levels of 168 dB. Since 168-168 = 0 
dB, 3 dB is added to the highest value, or 171 dB in total for the 
combination of 24-, 36-, and 42-inch steel pipe piles (NMFS, 2021d). By 
using this method, revised proxy SPLs were determined for the use of 
two 102-inch diameter rotary drills and the use of two 108-inch rotary 
drills and one 9-inch DTH mono-hammer. The revised proxy values are 
presented in Table 10 and the resulting harassment zones are summarized 
in Table 11 (visually depicted in Figures 6-21 and 6-22 in the Navy's 
application).

                  Table 10--Revised Proxy Values for Simultaneous Use of Non-Impulsive Sources
----------------------------------------------------------------------------------------------------------------
                       Source A                                         Source B
-------------------------------------------------------------------------------------------------  Revised proxy
                                        RMS SPL (dB re                            RMS SPL (dB re  RMS SPL (dB re
               Equipment                 1 [micro]Pa)           Equipment          1 [micro]Pa)    1 [micro]Pa)
----------------------------------------------------------------------------------------------------------------
Rotary Drill..........................             154  Rotary Drill............             154             157
Two Rotary Drills.....................             157  DTH Mono-Hammer.........             167             167
----------------------------------------------------------------------------------------------------------------


               Table 11--Level A and Level B Harassment Zones Resulting From Concurrent Activities
----------------------------------------------------------------------------------------------------------------
                                                      Level A harassment                    Level B harassment
                                      --------------------------------------------------------------------------
       Multiple source scenario             High frequency
                                          cetaceans (harbor         Phocid pinnipeds           All species
                                              porpoise)
----------------------------------------------------------------------------------------------------------------
2 Rotary Drills (9 hrs)..............  23.6 m/0.001514 km\2\..  9.7 m/0.000294 km\2\...  2,929 m/0.417417 km\2\.
2 Rotary Drills (9 hrs) and 1 DTH      74.2 m/0.012773 km\2\..  30.5 m/0.002489 km\2\..  13,594 m/0.417417
 Mono-Hammer (5 hrs).                                                                     km\2\.
----------------------------------------------------------------------------------------------------------------


[[Page 19521]]

Marine Mammal Occurrence and Take Estimation

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information, that 
inform the take calculations. We also describe how the information 
provided above is synthesized to produce a quantitative estimate of the 
take that is reasonably likely to occur.
    Potential exposures to impact and vibratory pile driving, rotary 
drilling, DTH, and rock hammering noise for each acoustic threshold 
were estimated using marine mammal density estimates (N) from the Navy 
Marine Species Density Database (NMSDD; Navy, 2017) or from monitoring 
reports from the Berth 11 Waterfront Improvements and P-310 
construction projects. Specifically, where monitoring data specific to 
the project area were available, they were used, and the NMSDD data 
were used when there were no monitoring data available. The take 
estimate was determined using the following equation: take estimate = N 
* days of activity * area of harassment. A 10 m shutdown zone designed 
to prevent animal interactions with equipment was subtracted from the 
Level A harassment zone, and the area of the Level A harassment zone 
was subtracted from the Level B harassment zone to avoid double 
counting of takes during these take calculations. Days of construction 
were conservatively based on relatively slow daily production rates. 
The pile type, size, and installation method that produce the largest 
zone of influence were used to estimate exposure of marine mammals to 
noise impacts. In instances where an activity will ensonify the entire 
ROI to the Level A harassment threshold, all potential takes are 
assumed to be by Level A harassment.
    Because some construction activities will occur over more than 1 
construction year, the number of takes per year were determined by the 
percent duration of each construction activity occurring each year 
(calculated by months). For example, if an activity were to occur for 6 
months, with 3 months occurring in year 2 and 3 months occurring in 
year 3, then 50 percent of the takes were assigned to year 2 and 50 
percent to year 3. In instances where only one take was calculated but 
activities spanned more than 1 construction year, one take was 
authorized for each construction year. Table 12 summarizes the 
calculated duration percentages for each activity that were used to 
divide take numbers by year.

                                                    Table 12--Division of Takes by Construction Year
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Total amount and estimated                                   Year 2 \1\   Year 3 \1\   Year 4 \1\   Year 5 \1\
              Activity ID                           dates                    Activity component         % takes      % takes      % takes      % takes
--------------------------------------------------------------------------------------------------------------------------------------------------------
(A1,2,3,4) Center Wall--Install         Drill 18 shafts Apr 23 to Aug  Install 102-inch diameter              100            0            0            0
 Foundation Support Piles.               23.                            outer casing.
                                                                       Pre-drill 102-inch outer               100            0            0            0
                                                                        casing.
                                                                       Remove 102-inch outer casing.          100            0            0            0
                                                                       Drill 79-inch diameter shaft.          100            0            0            0
(R) Dry Dock 1 North Entrance--Install  Install 48 sheet piles Apr 23  28-inch wide Z-shaped sheets.          100            0            0            0
 Temporary Cofferdam.                    to May 23.
(1) Berth 11--Remove Shutter Panels...  Remove 112 panels Apr 23 to    Concrete shutter panels......          100            0            0            0
                                         Apr 23.
(2) Berth 1--Remove Sheet Piles.......  Remove 168 sheet piles Apr 23  25-inch-wide Z-shaped........           80           20            0            0
                                         to Jun 24.
(3) Berth 1--Remove Granite Block Quay  2,800 cy Apr 23 to Jun 24....  Removal of granite blocks....           80           20            0            0
 Wall.
(4) Berth 1--Top of Wall Removal for    320 lf Apr 23 to Jun 24......  Mechanical concrete removal..           80           20            0            0
 Waler Installation.
(5) Berth 1--Install southeast corner   Install 28 sheet piles Apr 23  28-inch-wide Z-shaped........          100            0            0            0
 SOE.                                    to Jul 23.
(6) Berth 11--Mechanical Rock Removal   700 cy Apr 23 to Aug 23......  Excavate Bedrock.............          100            0            0            0
 at Basin Floor.
(7) Berth 11 Face--Mechanical Rock      Drill 924 relief holes Apr 23  4-6 inch diameter holes......          100            0            0            0
 Removal at Basin Floor.                 to Aug 23.
(8) Temporary Cofferdam Extension.....  Install 14 sheet piles Apr 23  28-inch-wide Z-shaped........          100            0            0            0
                                         to Jun 23.
(9a, b, c, d) Gantry crane Support      Drill 16 shafts Apr 23 to Aug  Set 102-inch diameter casing.          100            0            0            0
 Piles at Berth 1 West.                  23.                           Pre-drill 102-inch rock                100            0            0            0
                                                                        socket.
                                                                       Remove 102-inch casing.......          100            0            0            0
                                                                       72-inch diameter shafts......          100            0            0            0
(10) Berth 1--Mechanical Rock Removal   500 cy Apr 23 to Sep 23......  Excavate Bedrock.............          100            0            0            0
 at Basin Floor.
(11) Dry Dock 1 North Entrance--Drill   Drill 50 rock anchors Apr 23   9-inch diameter holes........          100            0            0            0
 Tremie Tie Downs.                       to Oct 23.
(12) Center Wall--Install Tie-In to     Install 15 sheet piles Apr 23  28-inch wide Z-shaped........          100            0            0            0
 Existing West Closure Wall.             to Dec 23.
(13a, b, c, d) Dry Dock 1 North--       Drill 20 shafts May 23 to Nov  Set 102-inch diameter casing.           60           40            0            0
 Temporary Piles.                        24.
                                                                       Pre-drill 102-inch rock                 60           40            0            0
                                                                        socket.
                                                                       Remove 102-inch casing.......           60           40            0            0
                                                                       84-inch diameter shafts......           60           40            0            0
(14) Dry Dock 1 North--Remove           Remove 20 piles May 23 to Nov  84-inch diameter drill piles.           60           40            0            0
 Temporary Work Trestle Piles.           24.
(15a, b, c, d) Dry Dock 1 North--       Drill 18 shafts May 23--Nov    Set 84-inch casing...........           60           40            0            0
 Install Leveling Piles (Diving Board    24.                           Pre-drill 84-inch rock socket           60           40            0            0
 Shafts).                                                              Remove 84-inch casing........           60           40            0            0
                                                                       78-inch diameter shaft.......           60           40            0            0
(16a, b, c, d) Wall Shafts for Dry      Drill 20 shafts Jun 23 to Nov  Set 102-inch diameter casing.           60           40            0            0
 Dock 1 North.                           24.                           Pre-drill 102-inch rock                 60           40            0            0
                                                                        socket.
                                                                       Remove 102-inch casing.......           60           40            0            0
                                                                       Drill 78-inch diameter shaft.           60           40            0            0
(17a, b, c, d) Foundation Shafts for    Drill 23 shafts Jun 23 to Nov  Set 126-inch diameter Casing.           60           40            0            0
 Dry Dock 1 North.                       24.                           Pre-drill 126-inch rock                 60           40            0            0
                                                                        socket.
                                                                       Remove 126-inch casing.......           60           40            0            0

[[Page 19522]]

 
                                                                       Drill 108-inch diameter                 60           40            0            0
                                                                        shafts.
(18) Berth 11 End Wall--Remove          Remove 60 sheet piles Jul 23   28-inch wide Z-shaped........          100            0            0            0
 Temporary Guide Wall.                   to Aug 23.
(19) Remove Berth 1 southeast corner    Remove 28 sheet piles Jul 23   28-inch-wide Z-shaped........          100            0            0            0
 SOE.                                    to Sep 23.
(20) Removal of Berth 1 Emergency       Remove 216 sheet piles Aug 23  28-inch-wide Z-shaped........          100            0            0            0
 Repair Sheet Piles.                     to Mar 24.
(21) Removal of Berth 1 Emergency       765 cubic meters (1,000 cy)    Mechanical concrete removal..          100            0            0            0
 Repair Tremie Concrete.                 Aug 23 to Mar 24.
(22) Center wall foundation--Drill in   Install 72 rock anchors Aug    9-inch diameter holes........           80           20            0            0
 monolith Tie Downs.                     23 to May 24.
(23) Center Wall--Remove tie-in to      Remove 16 sheet piles Aug 23   28-inch-wide Z-shaped........           60           40            0            0
 existing west closure wall (Dry Dock    to Aug 24.
 1 North).
(24) Center wall East--sheet pile tie-  Install 23 sheet piles Aug 23  28-inch wide Z-shaped........           50           50            0            0
 in to Existing Wall.                    to Oct 24.
(25) Remove tie-in to West Closure      Remove 15 sheet pile Dec 23    28-inch wide Z-shaped........           30           70            0            0
 Wall (Dry Dock 1 West).                 to Dec 24.
(26) Remove Center wall East--sheet     Remove 23 sheet piles Dec 23   28-inch wide Z-shaped........           30           70            0            0
 pile tie-in to Existing Wall (Dry       to Dec 24.
 Dock 1 West).
(27) Dry Dock 1 north entrance--Remove  Remove 96 sheet piles Jan 24   28-inch wide Z-shaped........           33           66            0            0
 Temporary Cofferdam.                    to Sep 24.
(28) Remove Temporary Cofferdam         Remove 14 sheet piles Jan 24   28-inch wide Z-shaped........           33           66            0            0
 Extension.                              to Sep 24.
(29a, b, c, d) Dry Dock 1 West--        Drill 20 shafts Apr 24 to Feb  Set 102-inch diameter casing.            0           50           50            0
 Install Temporary Piles.                26.                           Pre-drill 102-inch rock                  0           50           50            0
                                                                        socket.
                                                                       Remove 102-inch casing.......            0           50           50            0
                                                                       84-inch diameter shafts......            0           50           50            0
(30) Dry Dock 1 West--Remove Temporary  Remove 20 piles Apr 24 to Feb  84-inch diameter piles.......            0           50           50            0
 Work Trestle Piles.                     26.
(31a, b, c, d) Wall Shafts for Dry      Drill 22 shafts Jun 24 to Feb  Set 102-inch diameter casing.            0           50           50            0
 Dock 1 West.                            26.                           Pre-drill 102-inch rock                  0           50           50            0
                                                                        socket.
                                                                       Remove 102-inch casing.......            0           50           50            0
                                                                       78-inch diameter shaft.......            0           50           50            0
(32a, b, c, d) Foundation Shafts for    Drill 23 shafts Jun 24 to Feb  Set 126-inch casing..........            0           50           50            0
 Dry Dock 1 West.                        26.                           Pre-drill 126-inch rock                  0           50           50            0
                                                                        socket.
                                                                       Remove 126-inch casing.......            0           50           50            0
                                                                       Drill 108-inch diameter shaft            0           50           50            0
(33a, b, c, d) Dry Dock 1 West--        Drill 18 shafts Jun 24 to Feb  Set 84-inch casing...........            0           50           50            0
 Install Leveling Piles (Diving Board    26.                           Pre-drill 84-inch rock socket            0           50           50            0
 Shafts).                                                              Remove 84-inch casing........            0           50           50            0
                                                                       Drill 78-inch diameter shaft.            0           50           50            0
(34) Dry Dock 1 North--Tie Downs......  Install 36 rock anchors Jul    9-inch diameter holes........            0           70           30            0
                                         24 to Jul 25.
(35) Dry Dock 1 West--Install Tie       Install 36 rock anchors Dec    9-inch diameter hole.........            0            0           30           70
 Downs.                                  25 to Dec 26.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Note, for the purposes of this analysis, the construction years are identified as years 2 through 5; takes for marine mammals during Year 1 of the
  Navy's construction activities were authorized in a previously issued IHA (87 FR 19886, April 6, 2022).

    We describe how the information provided above is brought together 
to produce a quantitative take estimate in the species sections below. 
A summary of authorized take is available in Table 16.

Harbor Porpoise

    Harbor porpoises are expected to be present in the project area 
from April to December. Based on density data from the NMSDD, their 
presence is highest in spring, decreases in summer, and slightly 
increases in fall. During construction monitoring in the project area, 
there were three harbor porpoise observations between April and 
December of 2017; two harbor porpoise observations in early August of 
2018; and one harbor porpoise observation in 2020 (Cianbro, 2018; Navy, 
2019; NAVFAC, 2021). There were no harbor porpoise observations in the 
project area in 2021 (NAVFAC, 2022). Given that monitoring data 
specific to the project area are available, the more general NMSDD data 
were not used to determine species density in the project area. 
Instead, the Navy used observation data from the 2017 and 2018 
construction monitoring for the Berth 11 Waterfront Improvements 
Project and determined that the density of harbor porpoise for the 
largest harassment zone was equal to 0.04/km\2\. Estimated take was 
calculated with this density estimate multiplied by the harassment zone 
multiplied by the days for each activity (see Table 13).

[[Page 19523]]



                                                                 Table 13--Estimated Take of Harbor Porpoise by Project Activity
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Level A             Take by Level A harassment            Level B             Take by Level B harassment
                                                                     Total     harassment ---------------------------------------------  harassment --------------------------------------------
 Activity ID     Year/activity           Purpose        Density   production      zone                                                      zone
                                                                     days       (km\2\)     Total    Year 2   Year 3   Year 4   Year 5    (km\2\)     Total    Year 2   Year 3   Year 4   Year 5
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
A...........  2 Rotary Drill.....  Center Wall--            0.04          18     0.000014        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Install
                                    Foundation
                                    Support Piles.
              2 Rotary Drill.....  Center Wall--            0.04          18     0.000248        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Install
                                    Foundation
                                    Support Piles.
              2 Rotary Drill.....  Center Wall--            0.04          18     0.000002        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Install
                                    Foundation
                                    Support Piles.
              2 DTH Cluster Drill  Center Wall--            0.04         117     0.417417        2        2        0        0        0     0.417417        0        0        0        0        0
                                    Install
                                    Foundation
                                    Support Piles.
R...........  2 Vibratory Pile     Dry Dock 1 North         0.04           6    0.0014041        0        0        0        0        0     0.417417        0        0        0        0        0
               Driving.             Entrance--Install
                                    Temporary
                                    Cofferdam.
              2 Impact Pile        Dry Dock 1 North         0.04           6     0.417417        0        0        0        0        0     0.417417        0        0        0        0        0
               Driving.             Entrance--Install
                                    Temporary
                                    Cofferdam.
1...........  2 Hydraulic Rock     Shutter Panel            0.04          56     0.417417        1        1        0        0        0     0.277858        0        0        0        0        0
               Hammer.              Demolition (112
                                    panels).
2...........  2-3 Vibratory        Remove Berth 1           0.04          42     0.000454        0        0        0        0        0     0.417417    \1\ 2        1        1        0        0
               Extraction.          Sheet Piles.
3...........  2-3 Hydraulic Rock   Removal of Granite       0.04          47     0.417417    \1\ 2        1        1        0        0     0.277858        0        0        0        0        0
               Hammer.              Quay Wall (2,800
                                    cy).
4...........  2-3 Hydraulic Rock   Berth 1 Top of           0.04          74     0.417417    \1\ 2        1        1        0        0     0.277858        0        0        0        0        0
               Hammer.              Wall Demolition
                                    for Waler Install
                                    (320 lf).
5...........  2 Vibratory Pile     Install Berth 1          0.04           8     0.000454        0        0        0        0        0     0.417417        0        0        0        0        0
               Driving.             Support of
                                    Excavation.
              2 Impact Pile        Berth 1 Support of       0.04           8     0.403411        0        0        0        0        0     0.417417        0        0        0        0        0
               Driving.             Excavation.
6...........  2 Hydraulic Rock     Mechanical Rock          0.04          60     0.417417        1        1        0        0        0     0.277858        0        0        0        0        0
               Hammer.              Removal (700 cy)
                                    at Berth 11 Basin
                                    Floor.
7...........  2 DTH Mono-hammer..  Relief Holes at          0.04          35     0.047675        0        0        0        0        0     0.417417        1        1        0        0        0
                                    Berth 11 Basin
                                    Floor.
8...........  2 Vibratory Pile     Install Temporary        0.04           4     0.000454        0        0        0        0        0     0.417417        0        0        0        0        0
               Driving.             Cofferdam
                                    Extension.
              2 Impact Pile        Temporary                0.04           4     0.403411        0        0        0        0        0     0.417417        0        0        0        0        0
               Driving.             Cofferdam
                                    Extension.
9...........  2 Rotary Drill.....  Gantry Crane             0.04          16     0.000014        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Support--Install
                                    Outer Casing.
              2 Rotary Drill.....  Gantry Crane             0.04          16     0.000248        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Support--Pre-
                                    Drill Socket.
              2 Rotary Drill.....  Gantry Crane             0.04          16     0.000002        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Support--Remove
                                    Outer Casing.
              2 DTH Cluster Drill  Gantry Crane             0.04          80     0.417417        1        1        0        0        0     0.417417        0        0        0        0        0
                                    Support Piles.
10..........  2 Hydraulic Rock     Mechanical Rock          0.04          25     0.417417        0        0        0        0        0     0.277858        0        0        0        0        0
               Hammer.              Removal (300 cy)
                                    at Berth 1 Basin
                                    Floor.
11..........  2 DTH Mono-hammer..  Dry Dock 1 North         0.04          25     0.073751        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Entrance Rock
                                    Anchors.
12..........  2 Vibratory Pile     Center Wall Tie-In       0.04           4     0.000454        0        0        0        0        0     0.417417        0        0        0        0        0
               Driving.             to Existing West
                                    Closure Wall.
              2 Impact Pile        Center Wall Tie-in       0.04           4     0.403411        0        0        0        0        0     0.417417        0        0        0        0        0
               Driving.             to West Closure
                                    Wall.
13..........  2-3 Rotary Drill...  Dry Dock 1 North         0.04          20     0.000014        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Temporary Work
                                    Trestle--Install
                                    Outer Casing.
              2-3 Rotary Drill...  Dry Dock 1 North         0.04          20     0.000248        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Temporary Work
                                    Trestle--Pre-
                                    Drill Socket.

[[Page 19524]]

 
              2-3 Rotary Drill...  Dry Dock 1 North         0.04          20     0.000002        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Temporary Work
                                    Trestle--Remove
                                    Outer Casing.
              2-3 DTH Cluster      Dry Dock 1 North         0.04          70     0.417417    \1\ 2        1        1        0        0     0.417417        0        0        0        0        0
               Drill.               Temporary Work
                                    Trestle.
14..........  2-3 Rotary Drill...  Remove Dry Dock 1        0.04          20     0.000002        0        0        0        0        0     0.417417        0        0        0        0        0
                                    North Temporary
                                    Work Trestle
                                    Piles.
15..........  2-3 Rotary Drill...  Dry Dock 1 North         0.04          18     0.000014        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Leveling Piles--
                                    Install Outer
                                    Casing.
              2-3 Rotary Drill...  Dry Dock 1 North         0.04          18     0.000248        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Leveling Piles--
                                    Pre-Drill Socket.
              2-3 Rotary Drill...  Dry Dock 1 North         0.04          18     0.000002        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Leveling Piles--
                                    Remove Outer
                                    Casing.
              2-3 DTH Cluster      Dry Dock 1 North         0.04         135     0.417417        2        1        1        0        0     0.417417        0        0        0        0        0
               Drill.               Leveling Piles
                                    (Diving Board
                                    Shafts).
16..........  2-3 Rotary Drill...  Dry Dock 1 North         0.04          20     0.000014        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Wall Shafts--
                                    Install Outer
                                    Casing.
              2-3 Rotary Drill...  Dry Dock 1 North         0.04          20     0.000248        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Wall Shafts--Pre-
                                    Drill Socket.
              2-3 Rotary Drill...  Dry Dock 1 North         0.04          20     0.000002        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Wall Shafts--
                                    Remove Outer
                                    Casing.
              2-3 DTH Cluster      Wall Shafts for          0.04         150     0.417417        3        2        1        0        0     0.417417        0        0        0        0        0
               Drill.               Dry Dock 1 North.
17..........  2-3 Rotary Drill...  Dry Dock 1 North         0.04          23     0.000014        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Foundation
                                    Shafts--Install
                                    Outer Casing.
              2-3 Rotary Drill...  Dry Dock 1 North         0.04          23     0.000248        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Foundation Shafts
                                    Pre-Drill Sockets.
              2-3 Rotary Drill...  Dry Dock 1 North         0.04          23     0.000002        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Foundation
                                    Shafts--Remove
                                    Outer Casing.
              2-3 DTH Cluster      Foundation Shafts        0.04         196     0.417417        3        2        1        0        0     0.417417        0        0        0        0        0
               Drill.               for Dry Dock 1
                                    North.
18..........  2 Vibratory          Berth 11 End Wall        0.04          10     0.001041        0        0        0        0        0     0.417417        0        0        0        0        0
               Extraction.          Temporary Guide
                                    Wall.
19..........  2 Vibratory          Remove Berth 1           0.04           5     0.001041        0        0        0        0        0     0.417417        0        0        0        0        0
               Extraction.          Support of
                                    Excavation.
20..........  2 Vibratory          Remove Berth 1           0.04          18     0.000733        0        0        0        0        0     0.417417        1        1        0        0        0
               Extraction.          Emergency Repairs.
21..........  2 Hydraulic Rock     Removal of               0.04          15     0.417417        0        0        0        0        0     0.277858        0        0        0        0        0
               Hammer.              Emergency Repair
                                    Concrete (500 cy)
                                    at Berth 1.
22..........  2-3 DTH Mono-hammer  Center Wall              0.04          36     0.073751        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Foundation Rock
                                    Anchors.
23..........  2-3 Vibratory        Dry Dock 1 North-        0.04           3     0.001041        0        0        0        0        0     0.417417        0        0        0        0        0
               Extraction.          Remove Center
                                    Wall Tie-in to
                                    West Closure Wall.
24..........  2-3 Vibratory Pile   Center Wall East         0.04          12     0.000185        0        0        0        0        0     0.417417        0        0        0        0        0
               Driving.             Tie-in to
                                    Existing Wall.
              2-3 Impact Pile      Center Wall East         0.04          12     0.334747        0        0        0        0        0     0.417417        0        0        0        0        0
               Driving.             Tie-in to
                                    Existing Wall.
25..........  2-3 Vibratory        Dry Dock 1 West          0.04           3     0.001041        0        0        0        0        0     0.417417        0        0        0        0        0
               Extraction.          Remove Center
                                    Wall Tie-in to
                                    West Closure Wall.
26..........  2-3 Vibratory        Remove Center Wall       0.04          12     0.001041        0        0        0        0        0     0.417417        0        0        0        0        0
               Extraction.          Tie-in to
                                    Existing Wall.
27..........  2-3 Vibratory        Remove Temporary         0.04          12     0.001041        0        0        0        0        0     0.417417        0        0        0        0        0
               Extraction.          Cofferdam.
28..........  2-3 Vibratory        Remove Temporary         0.04           2     0.001041        0        0        0        0        0     0.417417        0        0        0        0        0
               Extraction.          Cofferdam
                                    Extension.

[[Page 19525]]

 
29..........  3-4 Rotary Drill...  Dry Dock 1 West          0.04          20     0.000014        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Temporary Work
                                    Trestle--Install
                                    Outer Casing.
              3-4 Rotary Drill...  Dry Dock 1 West          0.04          20     0.000248        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Temporary Work
                                    Trestle--Pre-
                                    Drill Socket.
              3-4 Rotary Drill...  Dry Dock 1 West          0.04          20     0.000002        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Temporary Work
                                    Trestle--Remove
                                    Outer Casing.
              3-4 DTH Cluster      Dry Dock 1 West          0.04          70     0.417417    \1\ 2        0        1        1        0     0.417417        0        0        0        0        0
               Drill.               Temporary Work
                                    Trestle.
30..........  3-4 Rotary Drill...  Dry Dock 1 West          0.04          20     0.000002        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Remove Temporary
                                    Work Trestle
                                    Piles.
31..........  3-4 Rotary Drill...  Dry Dock 1 West          0.04          22     0.000014        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Wall Shafts--
                                    Install Outer
                                    Casing.
              3-4 Rotary Drill...  Dry Dock 1 West          0.04          22     0.000248        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Wall Shafts--Pre-
                                    Drill Socket.
              3-4 Rotary Drill...  Dry Dock 1 West          0.04          22     0.000002        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Wall Shafts--
                                    Remove Outer
                                    Casing.
              3-4 DTH Cluster      Wall Shafts for          0.04         165     0.417417        3        0        1        2        0     0.417417        0        0        0        0        0
               Drill.               Dry Dock 1 West.
32..........  3-4 Rotary Drill...  Dry Dock 1 West          0.04          23     0.000014        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Foundation
                                    Shafts--Install
                                    Outer Casing.
              3-4 Rotary Drill...  Dry Dock 1 West          0.04          23     0.000248        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Foundation Shafts
                                    Pre-Drill Sockets.
              3-4 Rotary Drill...  Dry Dock 1 West          0.04          23     0.000002        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Foundation
                                    Shafts--Remove
                                    Outer Casing.
              3-4 DTH Cluster      Foundation Shafts        0.04         196     0.417417        3        0        1        2        0     0.417417        0        0        0        0        0
               Drill.               for Dry Dock 1
                                    West.
33..........  3-4 Rotary Drill...  Dry Dock 1 North         0.04          18     0.000014        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Leveling Piles--
                                    Install Outer
                                    Casing.
              3-4 Rotary Drill...  Dry Dock 1 West          0.04          18     0.000248        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Leveling Piles--
                                    Pre-Drill Socket.
              3-4 Rotary Drill...  Dry Dock 1 North         0.04          18     0.000002        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Leveling Piles--
                                    Remove Outer
                                    Casing.
              3-4 DTH Cluster      Dry Dock 1 West          0.04         135     0.417417        2        0        1        1        0     0.417417        0        0        0        0        0
               Drill.               Leveling Piles
                                    (Diving Board
                                    Shafts).
34..........  3-4 DTH Mono-hammer  Dry Dock 1 North         0.04          18     0.073751        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Rock Anchors.
35..........  4-5 DTH Mono-hammer  Dry Dock 1 West          0.04          18     0.073751        0        0        0        0        0     0.417417        0        0        0        0        0
                                    Rock Anchors.
                                                      ------------------------------------------------------------------------------------------------------------------------------------------
  Total.....  ...................  ..................  .........  ..........  ...........       29       13       10        6        0  ...........        4        3    \2\ 2        0        0
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
* Note: for the purposes of this analysis, the construction years are identified as years 2 through 5; takes for marine mammals during Year 1 of the Navy's construction activities were
  authorized in a previously issued IHA (87 FR 19886, April 6, 2022).
\1\ In instances where only 1 take was calculated but activities spanned more than 1 construction year, 1 take was requested by the Navy for each construction year.
\2\ 1 take by Level B harassment was added to construction year 3 to account for average group size of harbor porpoises (see https://www.fisheries.noaa.gov/species/harbor-
  porpoise#:~:text=The%20harbor%20porpoise%20is%20a,estuaries%2C%20harbors%2C%20and%20fjords).
** No additional takes are expected to result from the simultaneous use of 2 rotary drills and a DTH mono-hammer in construction years 3 and 4 and the simultaneous use of 2 rotary drills in
  construction year 4.


[[Page 19526]]

    Although no construction activity is currently planned for the 
final year of the LOA period (construction year 6), potential schedule 
slips may occur as a result of equipment failure, inclement weather, or 
other unforeseen events. However, potential takes that could occur 
during year 6 as a result of delays to activities scheduled for years 
2-5 are accounted for through the analyses for those years, and no 
additional take is authorized.

Harbor Seal

    Harbor seals may be present year-round in the project vicinity, 
with consistent densities throughout the year. Harbor seals are the 
most common pinniped in the Piscataqua River near the Shipyard. 
Sightings of this species were recorded during monthly surveys 
conducted in 2017 and 2018 (NAVFAC Mid-Atlantic, 2018, 2019b) as well 
as during Berth 11 and P-310 construction monitoring in 2017, 2018, 
2020 and 2021 (Cianbro, 2018; Navy, 2019; NAVFAC, 2021, 2022), and 
therefore density estimates from these efforts were considered in the 
analysis. Based on observations recorded during the Berth 11 Waterfront 
Improvements (199 observations of harbor seals during year 1 and 249 
observations of harbor seals during year 2 [448 total] over 322 days) 
and P-310 project construction monitoring (721 observations of harbor 
seals during year 1 and 451 observations of harbor seals during year 2 
[1,172 total] over 349 days), harbor seal density was estimated to be 
3.0/km\2\ in the project area (Cianbro, 2018; Navy, 2019; NAVFAC, 2021, 
2022).
    Takes by Level A harassment were calculated for harbor seals where 
the density of animals (3 harbor seals/km\2\) was multiplied by the 
harassment zone and the number of days per construction activity. This 
method was deemed to be inappropriate by the Navy for calculating takes 
by Level B harassment for harbor seals as it produced take numbers that 
were lower than the number of harbor seals that has been previously 
observed in the Navy's monitoring reports. Therefore, the Navy proposed 
(and NMFS concurred) to increase the estimated take by Level B 
harassment to more accurately reflect harbor seal observations in the 
monitoring reports, by using the value of three harbor seals observed a 
day multiplied by the total number of construction days (i.e., 349 
days), resulting in 1,047 takes per year by Level B harassment. This 
method is consistent with the methodology used to estimate takes by 
Level B harassment in IHA issued by NMFS for the first year of P-381 
construction activities (87 FR 19866, April 6, 2022).
    Additional takes by Level B harassment may occur during the 
simultaneous use of two rotary drills and a DTH mono-hammer in 
construction years 3 and 4 and the simultaneous use of two rotary 
drills in construction year 4. The simultaneous use of 2 rotary drills 
will result in 28 additional takes by Level B harassment of harbor 
seals. The simultaneous use of 2 rotary drills and a DTH mono-hammer 
will result in 22 additional takes by Level B harassment of harbor 
seals. Note, the use of cluster drills and rock hammers in construction 
years 2 and 3 result in the entire ROI being ensonified to Level A 
harassment thresholds; therefore, there will be no change to the size 
of the harassment zones from concurrent construction activities during 
these years and thus no need to authorize additional takes. To account 
for concurrent activities in construction years 3 and 4, the Navy 
requested to add additional takes by Level B harassment to the 
estimated take numbers (22 harbor seal in construction year 3 and 50 
harbor seal in construction year 4). Therefore the Navy requests and 
NMFS authorizes 1,047 takes by Level B harassment for harbor seals in 
construction year 2, 1,069 takes by Level B harassment for harbor seals 
in construction year 3, 1,097 takes by Level B harassment for harbor 
seals in construction year 4, and 1,047 takes by Level B takes for 
harbor seals in construction year 5 (note the division of takes over 
the construction years is summarized in Table 12).
    Take by Level A harassment of harbor seals is shown in Table 14 
below. Note that where the Level A harassment zone is as large as the 
Level B harassment zone and fills the entire potentially ensonified 
area, the enumerated takes in the Level A harassment column may be in 
the form of Level A harassment and/or Level B harassment, but are 
authorized as takes by Level A harassment. The authorized takes by 
Level B harassment are not included in Table 14 as they were calculated 
by a different method (i.e., by using the value of three harbor seals 
observed per day multiplied by the total number of construction days; 
i.e., 349 days).

                                    Table 14--Estimated Take by Level A Harassment of Harbor Seal by Project Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                  Level A             Take by Level A harassment
                                                                                      Total      harassment --------------------------------------------
           Activity ID              Year/ activity          Purpose       Density   production    zone (km
                                                                                       days         \2\)      Total    Year 2   Year 3   Year 4   Year 5
--------------------------------------------------------------------------------------------------------------------------------------------------------
A...............................  2 Rotary Drill....  Center Wall--             3           18     0.000005        0        0        0        0        0
                                                       Install
                                                       Foundation
                                                       Support Piles.
                                  2 Rotary Drill....  Center Wall--             3           18     0.000091        0        0        0        0        0
                                                       Install
                                                       Foundation
                                                       Support Piles.
                                  2 Rotary Drill....  Center Wall--             3           18     0.000001        0        0        0        0        0
                                                       Install
                                                       Foundation
                                                       Support Piles.
                                  2 DTH Cluster       Center Wall--             3          117     0.417417      147      147        0        0        0
                                   Drill.              Install
                                                       Foundation
                                                       Support Piles.
R...............................  2 Vibratory Pile    Dry Dock 1 North          3            6       0.0002        0        0        0        0        0
                                   Driving.            Entrance--Install
                                                       Temporary
                                                       Cofferdam.
                                  2 Impact Pile       Dry Dock 1 North          3            6     0.364953        7        7        0        0        0
                                   Driving.            Entrance--Install
                                                       Temporary
                                                       Cofferdam.
1...............................  2 Hydraulic Rock    Shutter Panel             3           56     0.417417       70       70        0        0        0
                                   Hammer.             Demolition (112
                                                       panels).
2...............................  2-3 Vibratory       Remove Berth 1            3           42     0.000078        0        0        0        0        0
                                   Extraction.         Sheet Piles.
3...............................  2-3 Hydraulic Rock  Removal of Granite        3           47     0.417417       59       47       12        0        0
                                   Hammer.             Quay Wall (2,800
                                                       cy).
4...............................  2-3 Hydraulic Rock  Berth 1 Top of            3           74     0.417417       93       74       19        0        0
                                   Hammer.             Wall Demolition
                                                       for Waler Install
                                                       (320 lf).
5...............................  2 Vibratory Pile    Install Berth 1           3            8     0.000078        0        0        0        0        0
                                   Driving.            Support of
                                                       Excavation.
                                  2 Impact Pile       Berth 1 Support of        3            8    0..201158        5        5        0        0        0
                                   Driving.            Excavation.

[[Page 19527]]

 
6...............................  2 Hydraulic Rock    Mechanical Rock           3           60     0.417417       75       75        0        0        0
                                   Hammer.             Removal (700 cy)
                                                       at Berth 11 Basin
                                                       Floor.
7...............................  2 DTH Mono-hammer.  Relief Holes at           3           35     0.014413        1        1        0        0        0
                                                       Berth 11 Basin
                                                       Floor.
8...............................  2 Vibratory Pile    Install Temporary         3            4     0.000078        0        0        0        0        0
                                   Driving.            Cofferdam
                                                       Extension.
                                  2 Impact Pile       Temporary                 3            4     0.201158        2        2        0        0        0
                                   Driving.            Cofferdam
                                                       Extension.
9...............................  2 Rotary Drill....  Gantry Crane              3           16     0.000005        0        0        0        0        0
                                                       Support--Install
                                                       Outer Casing.
                                  2 Rotary Drill....  Gantry Crane              3           16     0.000091        0        0        0        0        0
                                                       Support--Pre-
                                                       Drill Socket.
                                  2 Rotary Drill....  Gantry Crane              3           16     0.000091        0        0        0        0        0
                                                       Support--Remove
                                                       Outer Casing.
                                  2 DTH Cluster       Gantry Crane              3           80     0.417417      100      100        0        0        0
                                   Drill.              Support Piles.
10..............................  2 Hydraulic Rock    Mechanical Rock           3           25     0.417417       31       31        0        0        0
                                   Hammer.             Removal (300 cy)
                                                       at Berth 1 Basin
                                                       Floor.
11..............................  2 DTH Mono-hammer.  Dry Dock 1 North          3           25     0.022912        2        2        0        0        0
                                                       Entrance Rock
                                                       Anchors.
12..............................  2 Vibratory Pile    Center Wall Tie-In        3            4     0.000078        0        0        0        0        0
                                   Driving.            to Existing West
                                                       Closure Wall.
                                  2 Impact Pile       Center Wall Tie-in        3            4     0.201158        2        2        0        0        0
                                   Driving.            to West Closure
                                                       Wall.
13..............................  2-3 Rotary Drill..  Dry Dock 1 North          3           20     0.000005        0        0        0        0        0
                                                       Temporary Work
                                                       Trestle--Install
                                                       Outer Casing.
                                  2-3 Rotary Drill..  Dry Dock 1 North          3           20     0.000091        0        0        0        0        0
                                                       Temporary Work
                                                       Trestle--Pre-
                                                       Drill Socket.
                                  2-3 Rotary Drill..  Dry Dock 1 North          3           20     0.000001        0        0        0        0        0
                                                       Temporary Work
                                                       Trestle--Remove
                                                       Outer Casing.
                                  2-3 DTH Cluster     Dry Dock 1 North          3           70     0.417417       88       53       35        0        0
                                   Drill.              TemporaryWork
                                                       Trestle.
14..............................  2-3 Rotary Drill..  Remove Dry Dock 1         3           20     0.000002        0        0        0        0        0
                                                       North Temporary
                                                       Work Trestle
                                                       Piles.
15..............................  2-3 Rotary Drill..  Dry Dock 1 North          3           18     0.000005        0        0        0        0        0
                                                       Leveling Piles--
                                                       Install Outer
                                                       Casing.
                                  2-3 Rotary Drill..  Dry Dock 1 North          3           18     0.000091        0        0        0        0        0
                                                       Leveling Piles--
                                                       Pre-Drill Socket.
                                  2-3 Rotary Drill..  Dry Dock 1 North          3           18     0.000001        0        0        0        0        0
                                                       Leveling Piles--
                                                       Remove Outer
                                                       Casing.
                                  2-3 DTH Cluster     Dry Dock 1 North          3          135     0.417417      169      101       68        0        0
                                   Drill.              Leveling Piles
                                                       (Diving Board
                                                       Shafts).
16..............................  2-3 Rotary Drill..  Dry Dock 1 North          3           20     0.000005        0        0        0        0        0
                                                       Wall Shafts--
                                                       Install Outer
                                                       Casing.
                                  2-3 Rotary Drill..  Dry Dock 1 North          3           20     0.000091        0        0        0        0        0
                                                       Wall Shafts--Pre-
                                                       Drill Socket.
                                  2-3 Rotary Drill..  Dry Dock 1 North          3           20     0.000001        0        0        0        0        0
                                                       Wall Shafts--
                                                       Remove Outer
                                                       Casing.
                                  2-3 DTH Cluster     Wall Shafts for           3          150     0.417417      188      113       75        0        0
                                   Drill.              Dry Dock 1 North.
17..............................  2-3 Rotary Drill..  Dry Dock 1 North          3           23     0.000005        0        0        0        0        0
                                                       Foundation
                                                       Shafts--Install
                                                       Outer Casing.
                                  2-3 Rotary Drill..  Dry Dock 1 North          3           23     0.000091        0        0        0        0        0
                                                       Foundation Shafts
                                                       Pre-Drill Sockets.
                                  2-3 Rotary Drill..  Dry Dock 1 North          3           23     0.000001        0        0        0        0        0
                                                       Foundation
                                                       Shafts--Remove
                                                       Outer Casing.
                                  2-3 DTH Cluster     Foundation Shafts         3          196     0.417417      245      147       98        0        0
                                   Drill.              for Dry Dock 1
                                                       North.
18..............................  2 Vibratory         Berth 11 End Wall         3           10       0.0002        0        0        0        0        0
                                   Extraction.         Temporary Guide
                                                       Wall.
19..............................  2 Vibratory         Remove Berth 1            3            5       0.0002        0        0        0        0        0
                                   Extraction.         Support of
                                                       Excavation.
20..............................  2 Vibratory         Remove Berth 1            3           18     0.000136        0        0        0        0        0
                                   Extraction.         Emergency Repairs.
21..............................  2 Hydraulic Rock    Removal of                3           15     0.417417       19       19        0        0        0
                                   Hammer.             Emergency Repair
                                                       Concrete (500 cy)
                                                       at Berth 1.
22..............................  2-3 DTH Mono-       Center Wall               3           36     0.022912        2        1        1        0        0
                                   hammer.             Foundation Rock
                                                       Anchors.
23..............................  2-3 Vibratory       Dry Dock 1 North--        3            3       0.0002        0        0        0        0        0
                                   Extraction.         Remove Center
                                                       Wall Tie-in to
                                                       West Closure Wall.
24..............................  2-3 Vibratory Pile  Center Wall East          3           12     0.000032        0        0        0        0        0
                                   Driving.            Tie-in to
                                                       Existing Wall.
                                  2-3 Impact Pile     Center Wall East          3           12     0.090757        3        2        1        0        0
                                   Driving.            Tie-in to
                                                       Existing Wall.
25..............................  2-3 Vibratory       Dry Dock 1 West           3            3       0.0002        0        0        0        0        0
                                   Extraction.         Remove Center
                                                       Wall Tie-in to
                                                       West Closure Wall.
26..............................  2-3 Vibratory       Remove Center Wall        3           12       0.0002        0        0        0        0        0
                                   Extraction.         Tie-in to
                                                       Existing Wall.
27..............................  2-3 Vibratory       Remove Temporary          3           12       0.0002        0        0        0        0        0
                                   Extraction.         Cofferdam.

[[Page 19528]]

 
28..............................  2-3 Vibratory       Remove Temporary          3            2       0.0002        0        0        0        0        0
                                   Extraction.         Cofferdam
                                                       Extension.
29..............................  3-4 Rotary Drill..  Dry Dock 1 West           3           20     0.000005        0        0        0        0        0
                                                       Temporary Work
                                                       Trestle--Install
                                                       Outer Casing.
                                  3-4 Rotary Drill..  Dry Dock 1 West           3           20     0.000091        0        0        0        0        0
                                                       Temporary Work
                                                       Trestle--Pre-
                                                       Drill Socket.
                                  3-4 Rotary Drill..  Dry Dock 1 West           3           20     0.000001        0        0        0        0        0
                                                       Temporary Work
                                                       Trestle--Remove
                                                       Outer Casing.
                                  3-4 DTH Cluster     Dry Dock 1 West           3           70     0.417417       88        0       44       44        0
                                   Drill.              Temporary Work
                                                       Trestle.
30..............................  3-4 Rotary Drill..  Dry Dock 1 West           3           20     0.000002        0        0        0        0        0
                                                       Remove Temporary
                                                       Work Trestle
                                                       Piles.
31..............................  3-4 Rotary Drill..  Dry Dock 1 West           3           22     0.000005        0        0        0        0        0
                                                       Wall Shafts--
                                                       Install Outer
                                                       Casing.
                                  3-4 Rotary Drill..  Dry Dock 1 West           3           22     0.000091        0        0        0        0        0
                                                       Wall Shafts--Pre-
                                                       Drill Socket.
                                  3-4 Rotary Drill..  Dry Dock 1 West           3           22     0.000001        0        0        0        0        0
                                                       Wall Shafts--
                                                       Remove Outer
                                                       Casing.
                                  3-4 DTH Cluster     Wall Shafts for           3          165     0.417417      206        0      103      103        0
                                   Drill.              Dry Dock 1 West.
32..............................  3-4 Rotary Drill..  Dry Dock 1 West           3           23     0.000005        0        0        0        0        0
                                                       Foundation
                                                       Shafts--Install
                                                       Outer Casing.
                                  3-4 Rotary Drill..  Dry Dock 1 West           3           23     0.000091        0        0        0        0        0
                                                       Foundation Shafts
                                                       Pre-Drill Sockets.
                                  3-4 Rotary Drill..  Dry Dock 1 West           3           23     0.000001        0        0        0        0        0
                                                       Foundation
                                                       Shafts--Remove
                                                       Outer Casing.
                                  3-4 DTH Cluster     Foundation Shafts         3          196     0.417417      245        0      122      123        0
                                   Drill.              for Dry Dock 1
                                                       West.
33..............................  3-4 Rotary Drill..  Dry Dock 1 North          3           18     0.000005        0        0        0        0        0
                                                       Leveling Piles--
                                                       Install Outer
                                                       Casing.
                                  3-4 Rotary Drill..  Dry Dock 1 West           3           18     0.000091        0        0        0        0        0
                                                       Leveling Piles--
                                                       Pre-Drill Socket.
                                  3-4 Rotary Drill..  Dry Dock 1 North          3           18     0.000001        0        0        0        0        0
                                                       Leveling Piles--
                                                       Remove Outer
                                                       Casing.
                                  3-4 DTH Cluster     Dry Dock 1 West           3          135     0.417417      169        0       84       85        0
                                   Drill.              Leveling Piles
                                                       (Diving Board
                                                       Shafts).
34..............................  3-4 DTH Mono-       Dry Dock 1North           3           18     0.022912        1        0        1        0        0
                                   hammer.             Rock Anchors.
35..............................  4-5 DTH Mono-       Dry Dock 1 West           3           18     0.022912        1        0        0        0        1
                                   hammer.             Rock Anchors.
                                                                         -------------------------------------------------------------------------------
    Total.......................  ..................  ..................  .......  ...........  ...........    2,018      999      663      355        1
--------------------------------------------------------------------------------------------------------------------------------------------------------
\*\ Note: for the purposes of this analysis, the construction years are identified as years 2 through 5; takes for marine mammals during Year 1 of the
  Navy's construction activities were authorized in a previously issued IHA (87 FR 19886, April 6, 2022).

    Although no construction activity is currently planned for the 
final year of the LOA period (construction year 6), potential schedule 
slips may occur as a result of equipment failure, inclement weather, or 
other unforeseen events. However, potential takes that could occur 
during year 6 as a result of delays to activities scheduled for years 
2-5 are accounted for through the analyses for those years, and no 
additional take is authorized.

Gray Seal

    Gray seals may be present year-round in the project vicinity, with 
consistent densities throughout the year. Gray seals are less common in 
the Piscataqua River than the harbor seal. A total of nine sightings of 
gray seals were recorded during P-310 construction monitoring (NAVFAC, 
2021, 2022). Density estimates of gray seals were based on the Berth 11 
Waterfront Improvements (24 observations of gray seals during year 1 
and 12 observations of gray seals during year 2 [36 total] over 322 
days) and P-310 project construction monitoring (47 observations of 
gray seals during year 1 and 21 observations of gray seals during year 
2 [68 total] over 349 days) and was estimated to be 0.2/km\2\ (Cianbro, 
2018; Navy, 2019; NAVFAC, 2021, 2022). These data were preferred in 
this analysis over the more general density data from the NMSDD.
    Takes by Level A harassment were calculated for gray seals where 
the density of animals (0.2 gray seals/km\2\) was multiplied by the 
harassment zone and the number of days per construction activity. This 
method was deemed to be inappropriate by the Navy for calculating takes 
by Level B harassment for gray seals as it produced take that were 
fewer than the number of gray seals that has been previously observed 
in the Navy's monitoring reports. Therefore, the Navy proposed (and 
NMFS concurred), to increase the take by Level B harassment to more 
accurately reflect gray seal observations in the monitoring reports, by 
using the value of 0.2 gray seals a day multiplied by the total number 
of construction days (i.e., 349 days) resulting in 70 takes by Level B 
harassment authorized per year. This method is consistent with the 
methodology used to estimate takes by Level B harassment in IHA issued 
by NMFS for the first year of P-381 construction activities (87 FR 
19866; April 6, 2022).
    Additional takes by Level B harassment may occur during the 
simultaneous use of two rotary drills and a DTH mono-hammer in 
construction years 3 and 4 and the simultaneous use of two rotary 
drills in construction year 4. The simultaneous use of two rotary 
drills will result in two additional Level B takes of gray seals. The 
simultaneous use of two rotary drills and a DTH mono-hammer will result 
in one additional Level B take of

[[Page 19529]]

gray seals. Note, the use of cluster drills and rock hammers in 
construction years 2 and 3 result in the entire ROI being ensonified to 
Level A harassment thresholds; therefore, there will be no change to 
the size of the harassment zones from concurrent construction 
activities during these years and thus no need to request additional 
takes. To account for concurrent activities in construction years 3 and 
4, the Navy requested additional takes by Level B harassment to the 
take numbers (one gray seal in construction year 3 and three gray seals 
in construction year 4). Therefore the Navy requests and NMFS 
authorizes 70 takes by Level B takes for gray seals in construction 
year 2, 71 takes by Level B harassment for gray seals in construction 
year 3, 73 takes by Level B harassment for gray seals in construction 
year 4, and 70 takes by Level B harassment for gray seals in 
construction year 5 (note the division of takes over the construction 
years is summarized in Table 12).
    Take by Level A harassment of gray seals is shown in Table 15 
below. Note that where the Level A harassment zone is as large as the 
Level B harassment zone and fills the entire potentially ensonified 
area, the enumerated takes in the Level A harassment column may be in 
the form of Level A harassment and/or Level B harassment, but will be 
authorized as takes by Level A harassment. The authorized takes by 
Level B harassment are not included in Table 15 as they were calculated 
by a different method (i.e., by using the value of 0.2 gray seals 
observed a day multiplied by the total number of construction days; 
i.e., 349 days).

                                     Table 15--Estimated Take by Level A Harassment of Gray Seal by Project Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                  Level A             Take by Level A harassment
                                                                                      Total      harassment --------------------------------------------
          Activity ID             Year/activity         Purpose         Density     production   zone  (km
                                                                                       days         \2\)      Total    Year 2   Year 3   Year 4   Year 5
--------------------------------------------------------------------------------------------------------------------------------------------------------
A.............................  2 Rotary Drill...  Center Wall--              0.2           18     0.000005        0        0        0        0        0
                                                    Install
                                                    Foundation
                                                    Support Piles.
                                2 Rotary Drill...  Center Wall--              0.2           18     0.000091        0        0        0        0        0
                                                    Install
                                                    Foundation
                                                    Support Piles.
                                2 Rotary Drill...  Center Wall--              0.2           18     0.000001        0        0        0        0        0
                                                    Install
                                                    Foundation
                                                    Support Piles.
                                2 DTH Cluster      Center Wall--              0.2          117     0.417417       10       10        0        0        0
                                 Drill.             Install
                                                    Foundation
                                                    Support Piles.
R.............................  2 Vibratory Pile   Dry Dock 1 North           0.2            6       0.0002        0        0        0        0        0
                                 Driving.           Entrance--Instal
                                                    l Temporary
                                                    Cofferdam.
                                2 Impact Pile      Dry Dock 1 North           0.2            6     0.364953        0        0        0        0        0
                                 Driving.           Entrance--Instal
                                                    l Temporary
                                                    Cofferdam.
1.............................  2 Hydraulic Rock   Shutter Panel              0.2           56     0.417417        5        5        0        0        0
                                 Hammer.            Demolition (112
                                                    panels).
2.............................  2-3 Vibratory      Remove Berth 1             0.2           42     0.000078        0        0        0        0        0
                                 Extraction.        Sheet Piles.
3.............................  2-3 Hydraulic      Removal of                 0.2           47     0.417417        4        3        1        0        0
                                 Rock Hammer.       Granite Quay
                                                    Wall (2,800 cy).
4.............................  2-3 Hydraulic      Berth 1 Top of             0.2           74     0.417417        6        5        1        0        0
                                 Rock Hammer.       Wall Demolition
                                                    for Waler
                                                    Install (320 lf).
5.............................  2 Vibratory Pile   Install Berth 1            0.2            8     0.000078        0        0        0        0        0
                                 Driving.           Support of
                                                    Excavation.
                                2 Impact Pile      Berth 1 Support            0.2            8     0.201158        0        0        0        0        0
                                 Driving.           of Excavation.
6.............................  2 Hydraulic Rock   Mechanical Rock            0.2           60     0.417417        5        5        0        0        0
                                 Hammer.            Removal (700 cy)
                                                    at Berth 11
                                                    Basin Floor.
7.............................  2 DTH Mono-hammer  Relief Holes at            0.2           35     0.014413        0        0        0        0        0
                                                    Berth 11 Basin
                                                    Floor.
8.............................  2 Vibratory Pile   Install Temporary          0.2            4     0.000078        0        0        0        0        0
                                 Driving.           Cofferdam
                                                    Extension.
                                2 Impact Pile      Temporary                  0.2            4     0.201158        0        0        0        0        0
                                 Driving.           Cofferdam
                                                    Extension.
9.............................  2 Rotary Drill...  Gantry Crane               0.2           16     0.000005        0        0        0        0        0
                                                    Support--Install
                                                    Outer Casing.
                                2 Rotary Drill...  Gantry Crane               0.2           16     0.000091        0        0        0        0        0
                                                    Support--Pre-
                                                    Drill Socket.
                                2 Rotary Drill...  Gantry Crane               0.2           16     0.000091        0        0        0        0        0
                                                    Support--Remove
                                                    Outer Casing.
                                2 DTH Cluster      Gantry Crane               0.2           80     0.417417        7        7        0        0        0
                                 Drill.             Support Piles.
10............................  2 Hydraulic Rock   Mechanical Rock            0.2           25     0.417417        2        2        0        0        0
                                 Hammer.            Removal (300 cy)
                                                    at Berth 1 Basin
                                                    Floor.
11............................  2 DTH Mono-hammer  Dry Dock 1 North           0.2           25     0.022912        0        0        0        0        0
                                                    Entrance Rock
                                                    Anchors.
12............................  2 Vibratory Pile   Center Wall Tie-           0.2            4     0.000078        0        0        0        0        0
                                 Driving.           In to Existing
                                                    West Closure
                                                    Wall.
                                2 Impact Pile      Center Wall Tie-           0.2            4     0.201158        0        0        0        0        0
                                 Driving.           in to West
                                                    Closure Wall.
13............................  2-3 Rotary Drill.  Dry Dock 1 North           0.2           20     0.000005        0        0        0        0        0
                                                    Temporary Work
                                                    Trestle--Install
                                                    Outer Casing.
                                2-3 Rotary Drill.  Dry Dock 1 North           0.2           20     0.000091        0        0        0        0        0
                                                    Temporary Work
                                                    Trestle--Pre-
                                                    Drill Socket.
                                2-3 Rotary Drill.  Dry Dock 1 North           0.2           20     0.000001        0        0        0        0        0
                                                    Temporary Work
                                                    Trestle--Remove
                                                    Outer Casing.
                                2-3 DTH Cluster    Dry Dock 1 North           0.2           70     0.417417        6        4        2        0        0
                                 Drill.             Temporary Work
                                                    Trestle.
14............................  2-3 Rotary Drill.  Remove Dry Dock 1          0.2           20     0.000002        0        0        0        0        0
                                                    North Temporary
                                                    Work Trestle
                                                    Piles.

[[Page 19530]]

 
15............................  2-3 Rotary Drill.  Dry Dock 1 North           0.2           18     0.000005        0        0        0        0        0
                                                    Leveling Piles--
                                                    Install Outer
                                                    Casing.
                                2-3 Rotary Drill.  Dry Dock 1 North           0.2           18     0.000091        0        0        0        0        0
                                                    Leveling Piles--
                                                    Pre-Drill Socket.
                                2-3 Rotary Drill.  Dry Dock 1 North           0.2           18     0.000001        0        0        0        0        0
                                                    Leveling Piles--
                                                    Remove Outer
                                                    Casing.
                                2-3 DTH Cluster    Dry Dock 1 North           0.2          135     0.417417       11        7        4        0        0
                                 Drill.             Leveling Piles
                                                    (Diving Board
                                                    Shafts).
16............................  2-3 Rotary Drill.  Dry Dock 1 North           0.2           20     0.000005        0        0        0        0        0
                                                    Wall Shafts--
                                                    Install Outer
                                                    Casing.
                                2-3 Rotary Drill.  Dry Dock 1 North           0.2           20     0.000091        0        0        0        0        0
                                                    Wall Shafts--Pre-
                                                    Drill Socket.
                                2-3 Rotary Drill.  Dry Dock 1 North           0.2           20     0.000001        0        0        0        0        0
                                                    Wall Shafts--
                                                    Remove Outer
                                                    Casing.
                                2-3 DTH Cluster    Wall Shafts for            0.2          150     0.417417       13        8        5        0        0
                                 Drill.             Dry Dock 1 North.
17............................  2-3 Rotary Drill.  Dry Dock 1 North           0.2           23     0.000005        0        0        0        0        0
                                                    Foundation
                                                    Shafts--Install
                                                    Outer Casing.
                                2-3 Rotary Drill.  Dry Dock 1 North           0.2           23     0.000091        0        0        0        0        0
                                                    Foundation
                                                    Shafts Pre-Drill
                                                    Sockets.
                                2-3 Rotary Drill.  Dry Dock 1 North           0.2           23     0.000001        0        0        0        0        0
                                                    Foundation
                                                    Shafts--Remove
                                                    Outer Casing.
                                2-3 DTH Cluster    Foundation Shafts          0.2          196     0.417417       16       10        6        0        0
                                 Drill.             for Dry Dock 1
                                                    North.
18............................  2 Vibratory        Berth 11 End Wall          0.2           10       0.0002        0        0        0        0        0
                                 Extraction.        Temporary Guide
                                                    Wall.
19............................  2 Vibratory        Remove Berth 1             0.2            5       0.0002        0        0        0        0        0
                                 Extraction.        Support of
                                                    Excavation.
20............................  2 Vibratory        Remove Berth 1             0.2           18     0.000136        0        0        0        0        0
                                 Extraction.        Emergency
                                                    Repairs.
21............................  2 Hydraulic Rock   Removal of                 0.2           15     0.417417        1        1        0        0        0
                                 Hammer.            Emergency Repair
                                                    Concrete (500
                                                    cy) at Berth 1.
22............................  2-3 DTH Mono-      Center Wall                0.2           36     0.022912        0        0        0        0        0
                                 hammer.            Foundation Rock
                                                    Anchors.
23............................  2-3 Vibratory      Dry Dock North-            0.2            3       0.0002        0        0        0        0        0
                                 Extraction.        Remove Center
                                                    Wall Tie-in to
                                                    West Closure
                                                    Wall.
24............................  2-3 Vibratory      Center Wall East           0.2           12     0.000032        0        0        0        0        0
                                 Pile Driving.      Tie-in to
                                                    Existing Wall.
                                2-3 Impact Pile    Center Wall East           0.2           12     0.090757        0        0        0        0        0
                                 Driving.           Tie-in to
                                                    Existing Wall.
25............................  2-3 Vibratory      Dry Dock 1 West            0.2            3       0.0002        0        0        0        0        0
                                 Extraction.        Remove Center
                                                    Wall Tie-in to
                                                    West Closure
                                                    Wall.
26............................  2-3 Vibratory      Remove Center              0.2           12       0.0002        0        0        0        0        0
                                 Extraction.        Wall Tie-in to
                                                    Existing Wall.
27............................  2-3 Vibratory      Remove Temporary           0.2           12       0.0002        0        0        0        0        0
                                 Extraction.        Cofferdam.
28............................  2-3 Vibratory      Remove Temporary           0.2            2       0.0002        0        0        0        0        0
                                 Extraction.        Cofferdam
                                                    Extension.
29............................  3-4 Rotary Drill.  Dry Dock 1 West            0.2           20     0.000005        0        0        0        0        0
                                                    Temporary Work
                                                    Trestle--Install
                                                    Outer Casing.
                                3-4 Rotary Drill.  Dry Dock 1 West            0.2           20     0.000091        0        0        0        0        0
                                                    Temporary Work
                                                    Trestle--Pre-
                                                    Drill Socket.
                                3-4 Rotary Drill.  Dry Dock 1 West            0.2           20     0.000001        0        0        0        0        0
                                                    Temporary Work
                                                    Trestle--Remove
                                                    Outer Casing.
                                3-4 DTH Cluster    Dry Dock 1 West            0.2           70     0.417417        6        0        3        3        0
                                 Drill.             Temporary Work
                                                    Trestle.
30............................  3-4 Rotary Drill.  Dry Dock 1 West            0.2           20     0.000002        0        0        0        0        0
                                                    Remove Temporary
                                                    Work Trestle
                                                    Piles.
31............................  3-4 Rotary Drill.  Dry Dock 1 West            0.2           22     0.000005        0        0        0        0        0
                                                    Wall Shafts--
                                                    Install Outer
                                                    Casing.
                                3-4 Rotary Drill.  Dry Dock 1 West            0.2           22     0.000091        0        0        0        0        0
                                                    Wall Shafts--Pre-
                                                    Drill Socket.
                                3-4 Rotary Drill.  Dry Dock 1 West            0.2           22     0.000001        0        0        0        0        0
                                                    Wall Shafts--
                                                    Remove Outer
                                                    Casing.
                                3-4 DTH Cluster    Wall Shafts for            0.2          165     0.417417       14        0        7        7        0
                                 Drill.             Dry Dock 1 West.
32............................  3-4 Rotary Drill.  Dry Dock 1 West            0.2           23     0.000005        0        0        0        0        0
                                                    Foundation
                                                    Shafts--Install
                                                    Outer Casing.
                                3-4 Rotary Drill.  Dry Dock 1 West            0.2           23     0.000091        0        0        0        0        0
                                                    Foundation
                                                    Shafts Pre-Drill
                                                    Sockets.
                                3-4 Rotary Drill.  Dry Dock 1 West            0.2           23     0.000001        0        0        0        0        0
                                                    Foundation
                                                    Shafts--Remove
                                                    Outer Casing.
                                3-4 DTH Cluster    Foundation Shafts          0.2          196     0.417417       16        0        8        8        0
                                 Drill.             for Dry Dock 1
                                                    West.
33............................  3-4 Rotary Drill.  Dry Dock 1 North           0.2           18     0.000005        0        0        0        0        0
                                                    Leveling Piles--
                                                    Install Outer
                                                    Casing.
                                3-4 Rotary Drill.  Dry Dock 1 West            0.2           18     0.000091        0        0        0        0        0
                                                    Leveling Piles--
                                                    Pre-Drill Socket.

[[Page 19531]]

 
                                3-4 Rotary Drill.  Dry Dock 1 North           0.2           18     0.000001        0        0        0        0        0
                                                    Leveling Piles--
                                                    Remove Outer
                                                    Casing.
                                3-4 DTH Cluster    Dry Dock 1 West            0.2          135     0.417417       11        0        6        5        0
                                 Drill.             Leveling Piles
                                                    (Diving Board
                                                    Shafts).
34............................  3-4 DTH Mono-      Dry Dock 1 North           0.2           18     0.022912        0        0        0        0        0
                                 hammer.            Rock Anchors.
35............................  4-5 DTH Mono-      Dry Dock 1 West            0.2           18     0.022912        0        0        0        0        0
                                 hammer.            Rock Anchors.
                                                                     -----------------------------------------------------------------------------------
    Total.....................  .................  .................  ...........  ...........  ...........      133       67       43       23        0
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Note: for the purposes of this analysis, the construction years are identified as years 2 through 5; takes for marine mammals during Year 1 of the
  Navy's construction activities were authorized in a previously issued IHA (87 FR 19886, April 6, 2022).

    Although no construction activity is currently planned for the 
final year of the LOA period (construction year 6), potential schedule 
slips may occur as a result of equipment failure, inclement weather, or 
other unforeseen events. However, potential takes that could occur 
during year 6 as a result of delays to activities scheduled for years 
2-5 are accounted for through the analyses for those years, and no 
additional take is authorized.

Hooded Seal

    Hooded seals may be present in the project vicinity from January 
through May, though their exact seasonal densities are unknown. In 
general, hooded seals are much rarer than the harbor seal and gray seal 
in the Piscataqua River. NMFS authorized one take by Level B harassment 
per month from January to May of a hooded seal for the Berth 11 
Waterfront Improvements Construction project (NMFS, 2018b) and for P-
310 (Super Flood Basin) (NMFS, 2016; NMFS, 2019; NMFS, 2021c). To date, 
the monitoring for those projects and for the density surveys have not 
recorded a sighting of hooded seal in the project area (Cianbro, 2018; 
NAVFAC Mid-Atlantic, 2018, 2019b; Navy 2019; NAVFAC, 2021, 2022). In 
order to guard against the potential for unauthorized take, the Navy 
again requested one take by Level B harassment of hooded seal per month 
(between the months of January and May) for each construction year. 
Therefore NMFS authorizes five takes by Level B harassment per year. 
Given the size of the shutdown zones in relation to the Level A 
harassment isopleths (see the Mitigation section below), NMFS also 
authorizes five takes by Level A harassment per year to safeguard 
against unauthorized take of hooded seals that may occur unnoticed in 
the Level A harassment zone for sufficient duration to incur PTS.

Harp Seal

    In general, harp seals are much rarer than the harbor seal and gray 
seal in the Piscataqua River. Harp seals were not observed during 
marine mammal monitoring or survey events that took place in 2017, 
2018, or 2021 (Cianbro, 2018; NAVFAC Mid-Atlantic, 2018, 2019b; Navy, 
2019; NAVFAC, 2021, 2022); however, two harp seals (n=2) were observed 
in the River in 2020 (Stantec, 2020), and another harp seal was 
observed in 2016 (NAVFAC Mid-Atlantic, 2016; NMFS, 2016). As above for 
hooded seals, NMFS is authorizing one take by Level B harassment of 
harp seal per month of construction (between the months of January and 
May) for each construction year as was authorized by NMFS for the Berth 
11 Waterfront Improvements Project (NMFS, 2018b) and for P-310 (Super 
Flood Basin) construction activities (NMFS, 2019, 2021a). Harp seals 
may occur in the area from January through May. Anticipating one Level 
B harassment harp seal take per month for 5 months per year during in-
water construction will guard against potential unauthorized take of 
this species. Given the size of the shutdown zones in relation to the 
Level A harassment isopleths (see the Mitigation section below), NMFS 
also authorizes five takes by Level A harassment per year to safeguard 
against unauthorized take of harp seals that may occur unnoticed in the 
Level A harassment zone for sufficient duration to incur PTS.
    Table 16 below summarizes the authorized take for all the species 
described above as a percentage of stock abundance.

                                              Table 16--Authorized Take as a Percentage of Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                         Authorized   Authorized
                                                                                                          take by      take by       Total      Percent
            Construction year                       Species                      Stock (NEST)             Level A      Level B     authorized   of stock
                                                                                                         harassment   harassment      take
--------------------------------------------------------------------------------------------------------------------------------------------------------
2--Apr 2023-Mar 2024....................  Harbor porpoise............  Gulf of Maine/Bay of Fundy                13            3           16       0.02
                                                                        (95,543).
                                          Harbor seal................  Western North Atlantic (61,336)          999        1,047        2,046       3.33
                                          Gray seal..................  Western North Atlantic                    67           70          137       0.03
                                                                        (451,600).
                                          Harp seal..................  Western North Atlantic (7.6                5            5           10      <0.01
                                                                        million).
                                          Hooded seal................  Western North Atlantic                     5            5           10      <0.01
                                                                        (593,500).
3--Apr 2024-Mar 2025....................  Harbor porpoise............  Gulf of Maine/Bay of Fundy                10            2           12       0.01
                                                                        (95,543).
                                          Harbor seal................  Western North Atlantic (61,336)          663        1,069        1,732       2.82
                                          Gray seal..................  Western North Atlantic                    43           71          114       0.03
                                                                        (451,600).
                                          Harp seal..................  Western North Atlantic (7.6                5            5           10      <0.01
                                                                        million).
                                          Hooded seal................  Western North Atlantic                     5            5           10      <0.01
                                                                        (593,500).
4--Apr 2025-Mar 2026....................  Harbor porpoise............  Gulf of Maine/Bay of Fundy                 6            0            6       0.01
                                                                        (95,543).

[[Page 19532]]

 
                                          Harbor seal................  Western North Atlantic (61,336)          355        1,097        1,452       2.37
                                          Gray seal..................  Western North Atlantic                    23           73           96       0.02
                                                                        (451,600).
                                          Harp seal..................  Western North Atlantic (7.6                5            5           10      <0.01
                                                                        million).
                                          >Hooded seal...............  Western North Atlantic                     5            5           10      <0.01
                                                                        (593,500).
5--Apr 2026-Mar 2027....................  Harbor porpoise............  Gulf of Maine/Bay of Fundy                 0            0            0          0
                                                                        (95,543).
                                          Harbor seal................  Western North Atlantic (61,336)            1        1,047        1,048       1.71
                                          Gray seal..................  Western North Atlantic                     0           70           70       0.02
                                                                        (451,600).
                                          Harp seal..................  Western North Atlantic (7.6                5            5           10      <0.01
                                                                        million).
                                          Hooded seal................  Western North Atlantic                     5            5           10      <0.01
                                                                        (593,500).
6--Apr 2027-Mar 2028....................  Harbor porpoise............  Gulf of Maine/Bay of Fundy                 0            0            0      <0.01
                                                                        (95,543).
                                          Harbor seal................  Western North Atlantic (61,336)            0            0            0      <0.01
                                          Gray seal..................  Western North Atlantic                     0            0            0      <0.01
                                                                        (451,600).
                                          Harp seal..................  Western North Atlantic (7.6                0            0            0      <0.01
                                                                        million).
                                          Hooded seal................  Western North Atlantic                     0            0            0      <0.01
                                                                        (593,500).
Total Authorized Take \1\...............  Harbor porpoise............  Gulf of Maine/Bay of Fundy                29            5           34         NA
                                                                        (95,543).
                                          Harbor seal................  Western North Atlantic (61,336)        2,018        4,260        6,278         NA
                                          Gray seal..................  Western North Atlantic                   133          284          438         NA
                                                                        (451,600).
                                          Harp seal..................  Western North Atlantic (7.6               25           25           50         NA
                                                                        million).
                                          Hooded seal................  Western North Atlantic                    25           25           50         NA
                                                                        (593,500).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The total authorized take does not include take that may occur in year 6 as a result of schedule delays, as these potential takes are already
  accounted for in previous years.

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 the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the 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 the 
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, NMFS 
considers 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.
    The following mitigation measures apply to the Navy's in-water 
construction activities.

General

    In-water construction activities 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. If such circumstances recur, the Navy will consult 
with NMFS concerning the potential need for an additional take 
authorization.

Coordination

    The Navy shall conduct briefings between construction supervisors 
and crews, the marine mammal monitoring team, and Navy staff prior to 
the start of in-water construction activities and when new personnel 
join the work, to ensure that responsibilities, communication 
procedures, marine mammal monitoring protocols, and operational 
procedures are clearly understood.

Soft Start

    The Navy shall use soft start techniques when impact pile driving. 
The objective of a soft start is to provide a warning and/or give 
animals in close proximity to pile-driving a chance to leave the area 
prior to an impact driver operating at full capacity, thereby exposing 
fewer animals to loud underwater and airborne sounds. Soft start 
requires contractors to provide an initial set of strikes from the 
impact hammer at reduced energy, followed by a 30-second waiting 
period, then two subsequent reduced-energy strike sets. Note the number 
of strikes will vary at reduced energy because raising the hammer at 
less than full power and then releasing it results in the hammer 
``bouncing'' as it strikes the pile, resulting in multiple ``strikes.'' 
A 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 applicable to other 
in-water construction activities.

Bubble Curtain

    During construction of the multifunctional expansion of Dry Dock 1, 
portions of the west closure wall and/or the super flood basin caisson 
gate may not be in place. A bubble curtain

[[Page 19533]]

will be installed across the entrance openings to mitigate underwater 
noise impacts outside of the basin for those activities where Level A 
harassment thresholds are achieved across the entire ROI (i.e., cluster 
drill and hydraulic rock hammering (Table 7)). A bubble curtain similar 
to the one employed during P-310 blasting activities and proposed for 
use during P-381 year 1 construction will be used to minimize potential 
impacts outside of the basin. Hydroacoustic monitoring will be 
conducted inside of the bubble curtain to measure construction 
generated noise levels. Should the results of the recordings inside the 
bubble curtain show that the source levels do not result in the Level A 
harassment thresholds being achieved across the entire ROI by the 
activity occurring, upon review of the data by NMFS, the Navy may 
discontinue use of the bubble curtain for those activities that are not 
actually exceeding thresholds. The bubble curtain must adhere to the 
following restrictions:
     The bubble curtain must distribute air bubbles across 100 
percent of the entrance openings for the full depth of the water 
column;
     The lowest bubble ring must be in contact with the 
substrate for the full extent of the curtain, and the weights attached 
to the bottom of the curtain must ensure 100 percent substrate contact. 
No parts of the curtain or other objects shall prevent full substrate 
contact; and
     Air flow to the bubblers must be balanced around the 
entrance openings to the superflood basin.

Avoiding Direct Physical Interaction

    During all in-water construction activities, in order to prevent 
injury from physical interaction with construction equipment, a 
shutdown zone of 10 m (33 ft) will be implemented. If a marine mammal 
comes within 10 m (33 ft) of such activity, operations shall cease and 
vessels will reduce speed to the minimum level required to maintain 
steerage and safe working conditions. If human safety is at risk, the 
in-water activity will be allowed to continue until it is safe to stop.

Shutdown Zones

    The Navy shall establish shutdown zones for all in-water 
construction activities. 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). Shutdown zones will vary based on the activity type 
and marine mammal hearing group (Table 17). The shutdown zone distances 
for rock hammering, impact pile-driving of sheet piles, and DTH 
excavation (200 m (656 ft) for harbor porpoise and 50 m (164 ft) for 
seals) are consistent with those implemented for the same activities 
for P-381 year 1 construction activities (NMFS, 2022a; 87 FR 19886, 
April 6, 2022). NMFS has determined that these shutdown zones represent 
the largest area that can practicably be monitored.

               Table 17--Pile Driving Shutdown Zone and Monitoring Zones During Project Activities
----------------------------------------------------------------------------------------------------------------
                                                                        Shutdown zone (m)
                                                                -------------------------------- Monitoring zone
           LOA year              Activity, size, and component       Harbor                        \1\ (km\2\)
                                                                    porpoise          Seals
----------------------------------------------------------------------------------------------------------------
2.............................  Rock Hammering \2\.............             200              50  ROI.\3\
2.............................  Impact Pile Driving--8 sheet                200              50  ROI.\4\
                                 piles per day.
2.............................  Impact Pile Driving--4 sheet                200              50  ROI.\4\
                                 piles per day.
2/3...........................  Impact Pile Driving--2 sheet                200              50  ROI.\4\
                                 piles per day.
2/3...........................  Vibratory Pile Driving/                      20              10  ROI.\4\
                                 Extraction--8 sheet piles per
                                 day.
2.............................  Vibratory Pile Driving/                      20              10  ROI.\4\
                                 Extraction--6 sheet piles per
                                 day.
2.............................  Vibratory Pile Driving/                      15              10  ROI.\4\
                                 Extraction--4 sheet piles per
                                 day.
2/3...........................  Vibratory Pile Driving/                      10              10  ROI.\4\
                                 Extraction--2 sheet piles per
                                 day.
2.............................  DTH mono-hammer 4-6 inch relief             180              50  ROI.\4\
                                 holes.
2/3/4/5.......................  DTH mono-hammer 9-inch rock                 200              50  ROI.\4\
                                 anchors for tie-downs.
2/3/4.........................  Rotary Drilling--1 hour to set               10              10  ROI.\4\
                                 casings.
2/3/4.........................  Rotary drilling--9 hours to                  10              10  ROI.\4\
                                 drill socket.
2/3/4.........................  Rotary Drilling--15 minutes to               10              10  ROI.\4\
                                 remove casings and temporary
                                 work trestle piles.
2/3/4.........................  Cluster Drilling \2\...........             200              50  ROI.\3\ \4\
----------------------------------------------------------------------------------------------------------------
\1\ In instances where the harassment zone is larger than the region of influence (ROI), the entire ROI is
  indicated as the limit of monitoring (see Figure 1-3 in the Navy's application).
\2\ Activities will employ a bubble curtain to reduce underwater noise impacts outside of the basin.
\3\ The entire ROI will be ensonified to the Level A threshold.
\4\ The entire ROI will be ensonified to the Level B threshold.

    The Navy must delay or shutdown in-water construction activities 
should a marine mammal approach or enter the appropriate shutdown zone. 
The Navy may resume activities after one of the following conditions 
have been met: (1) the animal is observed exiting the shutdown zone; 
(2) the animal is thought to have exited the shutdown zone based on a 
determination of its course, speed, and movement relative to the pile 
driving location; or (3) the shutdown zone has been clear from any 
additional sightings for 15 minutes.

Protected Species Observers

    The Navy shall employ at least three protected species observers 
(PSOs) to monitor marine mammal presence in the action area during all 
in-water construction activities. Additional PSOs may be added if 
warranted by site conditions (rough seas, rain) and the level of marine 
mammal activity. All PSOs will be approved by NMFS and the Navy prior 
to starting work as a PSO. PSOs must track marine mammals observed 
anywhere within their visual range relative to in-water construction 
activities, and estimate the amount of time a marine mammal spends 
within the Level A or Level B harassment zones while construction 
activities are underway.
    Monitoring must take place from 30 minutes prior to initiation of 
pile driving or drilling activity (i.e., pre-start clearance 
monitoring) through 30

[[Page 19534]]

minutes post-completion of pile driving or drilling activity. Pre-start 
clearance monitoring must be conducted for 30 minutes to ensure that 
the shutdown zones indicated in Table 17 are clear of marine mammals, 
and pile driving or drilling may commence when observers have declared 
the shutdown zone clear of marine mammals. Monitoring must occur 
throughout the time required to drive/drill a pile. If work ceases for 
more than 30 minutes, the pre-start clearance 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).
    The placement of PSOs during all pile driving and drilling 
activities (described in the Monitoring and Reporting section) must 
ensure that the entire shutdown zone and Level A harassment zone is 
visible during pile driving and drilling. Should environmental 
conditions deteriorate such that marine mammals within the entire 
shutdown zone or Level A harassment zone will not be visible (e.g., 
fog, heavy rain), in-water construction activities must be delayed 
until the PSO is confident marine mammals within the shutdown zone or 
Level A harassment zone could be detected. However, if work on a pile 
has already begun, work is allowed to continue until that pile is 
installed.
    If an in-water construction activity is delayed or halted due to 
the presence of a marine mammal, the activity may not commence or 
resume until either the animal has voluntarily exited and been visually 
confirmed beyond the shutdown zone indicated in Table 17 or 15 minutes 
have passed without re-detection of the animal. If in-water 
construction activities cease for more than 30 minutes, the pre-
activity monitoring of the shutdown zone must commence.
    Based on our evaluation of the applicant's planned measures, NMFS 
has determined that the 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.

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. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present while 
conducting the activities. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Under the MMPA implementing regulations, monitoring and reporting 
requirements prescribed by NMFS should contribute to improved 
understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and,
     Mitigation and monitoring effectiveness.
    The Navy shall submit a Marine Mammal Monitoring Plan to NMFS for 
approval in advance of the start of the construction covered by this 
rule. The plan will incorporate all monitoring and mitigation measures 
and reporting requirements of the incidental take regulations.

Monitoring Zones

    The Navy shall conduct monitoring to include the entire ROI, which 
includes the area within the Level B harassment zones (areas where SPLs 
are equal to or exceed the 160 dB RMS threshold for impact driving and 
hydraulic rock hammering, and the 120 dB RMS threshold during vibratory 
pile driving, rotary drilling, and DTH) (see Table 7 and 8). These 
monitoring zones provide utility for monitoring conducted for 
mitigation purposes (i.e., shutdown zone monitoring) by establishing 
monitoring protocols for areas adjacent to the shutdown zones. 
Monitoring of these zones enables observers to be aware of and 
communicate the presence of marine mammals in the project area, but 
outside the shutdown zone, and thus prepare for potential shutdowns of 
activity.

Protected Species Observer (PSO) Monitoring Requirements and Locations

    PSOs shall be responsible for monitoring the shutdown zones, the 
monitoring zones and the pre-clearance zones, as well as effectively 
documenting takes by Level A and B harassment. As described in more 
detail in the Marine Mammal Monitoring Reporting section below, they 
shall also (1) document the frequency at which marine mammals are 
present in the project area, (2) document behavior and group 
composition, (3) record all construction activities, and (4) document 
observed reactions (changes in behavior or movement) of marine mammals 
during each sighting. The PSOs shall monitor for marine mammals during 
all in-water construction activities associated with the project. The 
Navy shall monitor the project area to the extent possible based on the 
required number of PSOs, required monitoring locations, and 
environmental conditions. Visual monitoring shall be conducted by three 
PSOs. It is assumed that three PSOs shall be located on boats, docks, 
or piers sufficient to monitor the respective ROIs given the abundance 
of suitable vantage points (see Figure 11-1 of the Navy's application). 
The PSOs must record all observations of marine mammals, regardless of 
distance from the in-water construction activity.
    Monitoring of in-water construction activities shall be conducted 
by qualified, PSOs. The Navy shall adhere to the following conditions 
when selecting PSOs:
    [ssquf] PSOs must be independent (i.e., not construction personnel) 
and have no other assigned tasks during monitoring periods;
    [ssquf] At least one PSO must have prior experience performing the 
duties of a PSO during construction activities pursuant to a NMFS-
issued incidental take authorization;
    [ssquf] Other PSOs may substitute other relevant experience, 
education (degree in biological science or related field), or training;

[[Page 19535]]

    [ssquf] Where a team of three PSOs are required, a lead observer or 
monitoring coordinator shall be designated. The lead observer must have 
prior experience performing the duties of a PSO during construction 
activity pursuant to a NMFS-issued incidental take authorization; and
    [ssquf] PSOs must be approved by NMFS prior to beginning any 
activity subject to this rule.
    The Navy will ensure that the PSOs have the following additional 
qualifications:
    [ssquf] Visual acuity in both eyes (correction is permissible) 
sufficient for discernment of moving targets at the water's surface 
with ability to estimate target size and distance; use of binoculars 
may be necessary to correctly identify the target;
    [ssquf] Experience and ability to conduct field observations and 
collect data according to assigned protocols;
    [ssquf] Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
    [ssquf] Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    [ssquf] 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
    [ssquf] 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.

Hydroacoustic Monitoring

    The Navy shall conduct a sound source verification (SSV) study 
effort to measure SPLs from in-water construction activities not 
previously monitored as part of P-310 or as part of P-381 year 1 
construction. The Navy will collect and evaluate acoustic sound record 
levels for the rock excavation (rotary drilling or DTH excavation) 
activities conducted up to a maximum limit of 10 piles/holes. One 
hydrophone will be placed at locations 10 m (33 ft) from the noise 
source and a second hydrophone will be placed at a representative 
monitoring location at an intermediate distance between the cetacean 
and phocid shutdown zones. These locations will be adhered to as 
practicable given safety considerations and levels of activity in the 
basin. For the 10 rock excavation (rotary drilling or DTH excavation) 
events acoustically measured, 100 percent of the data will be analyzed.
    At a minimum, the methodology includes:
    [ssquf] For underwater recordings, a stationary hydrophone system 
with the ability to measure SPLs will be placed in accordance with 
NMFS' most recent guidance for the collection of source levels (NMFS, 
2012).
    [ssquf] Hydroacoustic monitoring will be conducted for each type of 
activity not previously monitored under P-310 or the P-381 year 1 IHA 
up to a maximum limit of 10 piles/holes (Table 18). Monitoring will 
occur from the same locations approved by NMFS for P-310 construction 
activities. The resulting data set will be analyzed to examine and 
confirm sound pressure levels and rates of TL for each separate in-
water construction activity. With NMFS concurrence, these measurements 
may be used to recalculate the limits of shutdown and Level A and Level 
B harassment zones, as appropriate. Hydrophones will be placed in the 
same manner as for P-310 construction activities. Locations of 
hydroacoustic recordings will be collected via global positioning 
system. A depth sounder and/or weighted tape measure will be used to 
determine the depth of the water. The hydrophone will be attached to a-
weighted nylon cord or chain to maintain a constant depth and distance 
from the pile/drill/hammer location. The nylon cord or chain will be 
attached to a float or tied to a static line.

                                   Table 18--Hydroacoustic Monitoring Summary
----------------------------------------------------------------------------------------------------------------
                                                    Number
             Pile type/shaft size                 installed/        Method of install/removal         Number
                                                    removed                                          monitored
----------------------------------------------------------------------------------------------------------------
126-inch shaft................................             138  Rotary Drill....................              10
84-inch shaft.................................             148  Rotary Drill....................              10
108-inch shaft................................              46  DTH Cluster Drill...............              10
84-inch shaft.................................              40  DTH Cluster Drill...............              10
72-inch shaft.................................              16  DTH Cluster Drill...............              10
----------------------------------------------------------------------------------------------------------------

    [ssquf] Each hydrophone will be calibrated at the start of each 
action and will be checked frequently to the applicable standards of 
the hydrophone manufacturer.
    [ssquf] For each monitored location, a single hydrophone will be 
suspended midway in the water column in order to evaluate site-specific 
attenuation and propagation characteristics that may be present 
throughout the water column.
    [ssquf] Environmental data will be collected, including but not 
limited to, the following: wind speed and direction, air temperature, 
humidity, surface water temperature, water depth, wave height, weather 
conditions, and other factors that could contribute to influencing the 
airborne and underwater sound levels (e.g., aircraft, boats, etc.).
    [ssquf] The chief inspector will supply the acoustics specialist 
with the substrate composition, hammer/drill model and size, hammer/
drill energy settings, depth of drilling, and boring rates and any 
changes to those settings during the monitoring.
    [ssquf] For acoustically monitored construction activities, data 
from the continuous monitoring locations will be post-processed to 
obtain the following sound measures:
    [cir] Maximum peak sound pressure level recorded for all 
activities, expressed in dB re 1 [mu]Pa. This maximum value will 
originate from the phase of drilling/hammering during which drill/
hammer energy was also at maximum (referred to as Level 4).
    [cir] From all activities occurring during the Level 4 phase these 
additional measures will be made, as appropriate:
    [ssquf] Mean, median, minimum, and maximum RMS sound pressure level 
in (dB re 1 [mu]Pa);
    [ssquf] Mean duration of a pile strike (based on the 90 percent 
energy criterion);
    [ssquf] Number of hammer strikes;
    [ssquf] Mean, median, minimum, and maximum single strike SEL (dB re 
[mu]Pa\2\ sec);
    [cir] Median integration time used to calculate SPL RMS (for 
vibration

[[Page 19536]]

monitoring, the time period selected is 1-second intervals. For 
impulsive monitoring, the time period is 90 percent of the energy pulse 
duration).
    [cir] A frequency spectrum (power spectral density) (dB re 
[mu]Pa\2\ per Hz) based on all strikes with similar sound. Spectral 
resolution will be 1 Hz, and the spectrum will cover nominal range from 
7 Hz to 20 kHz.
    [cir] Finally, the cumulative SEL will be computed from all the 
strikes associated with each pile occurring during all phases, i.e., 
soft start, Level 1, to Level 4. This measure is defined as the sum of 
all single strike SEL values. The sum is taken of the antilog, with 
log10 taken of result to express (dB re [mu]Pa\2\ sec).

Marine Mammal Monitoring Reporting

    The Navy shall submit annual draft reports to NMFS for each 
construction year within 90 calendar days of the completion of marine 
mammal monitoring as well as a draft 5-year comprehensive summary 
report at the end of the project. The report(s) will detail the 
monitoring protocol and summarize the data recorded during monitoring. 
Annual reports will also include results from acoustic monitoring (see 
below). Final annual report(s) (each portion of the project and 
comprehensive) must be prepared and submitted to NMFS within 30 days 
following resolution of any NMFS comments on the draft reports. If no 
comments are received from NMFS within 30 days of receipt of the draft 
report, the report shall be considered final. If comments are received, 
a final report addressing NMFS comments must be submitted within 30 
days after receipt of comments.
    A draft 5-year comprehensive summary report shall be submitted to 
NMFS 90 days after the expiration of the regulations. The draft report 
will synthesize the data recorded during hydroacoustic and marine 
mammal monitoring. NMFS will provide comments within 30 days after 
receiving this draft report, and the Navy will address the comments and 
submit revisions within 30 days of receipt. If no comment is received 
from NMFS within 30 days, the draft report will be considered as final.
    All draft and final marine mammal monitoring reports must be 
submitted to [email protected] and 
[email protected]. The report must contain the following 
informational elements, at minimum, (and be included in the Marine 
Mammal Monitoring Plan), including:
    [ssquf] Dates and times (begin and end) of all marine mammal 
monitoring;
    [ssquf] Construction activities occurring during each daily 
observation period, including:
    [cir] How many and what type of piles/shafts were driven and by 
what method (e.g., impact, vibratory, rotary drilling, rock hammering, 
mono- or cluster-DTH); and
    [cir] Total duration of driving time for each pile/hole (vibratory 
driving, rotary drilling) and number of strikes for each pile/hole 
(impact driving, hydraulic rock hammering); and
    [cir] For DTH excavation, the duration of operation for both 
impulsive and non-pulse components, as well as the strike rate.
    [ssquf] PSO locations during marine mammal monitoring;
    [ssquf] 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;
    [ssquf] Upon observation of a marine mammal, the following 
information:
    [cir] PSO who sighted the animal and PSO location and activity at 
time of sighting;
    [cir] Time of sighting;
    [cir] Identification of the animal (e.g., genus/species, lowest 
possible taxonomic level, or unidentified), PSO confidence in 
identification, and the composition of the group if there is a mix of 
species;
    [cir] Distance and bearing of each marine mammal observed relative 
to the in-water construction activity for each sighting (if the in-
water construction was occurring at time of sighting);
    [cir] Estimated number of animals (minimum/maximum/best);
    [cir] Estimated number of animals by cohort (adults, juveniles, 
neonates, group composition, etc.;
    [cir] Animal's closest point of approach and estimated time spent 
within each harassment zone; and
    [cir] Description of any marine mammal behavioral observations 
(e.g., observed behaviors such as feeding or traveling), including an 
assessment of behavioral responses to the activity (e.g., no response 
or changes in behavioral state such as ceasing feeding, changing 
direction, flushing, or breaching);
    [ssquf] Number of marine mammals detected within the harassment 
zones, by species;
    [ssquf] Detailed information about implementation of any mitigation 
(e.g., shutdowns and delays), a description of specific actions that 
ensued, and resulting changes in behavior of the animal, if any; and
    [ssquf] All PSO datasheets and/or raw sightings data.
    The draft and final reports must also contain the informational 
elements described in the Hydroacoustic Monitoring Plan which, at 
minimum, must include:
    [ssquf] Hydrophone equipment and methods: recording device, 
sampling rate, distance (m) from the pile where recordings were made; 
depth of water and recording device(s);
    [ssquf] Type and size of pile being driven, substrate type, method 
of driving during recordings (e.g., hammer model and energy), and total 
pile driving duration;
    [ssquf] Whether a sound attenuation device is used and, if so, a 
detailed description of the device used and the duration of its use per 
pile;
    [ssquf] For impact pile driving and/or DTH excavation (DTH mono-
hammer and cluster drill) (per pile): Number of strikes and strike 
rate; depth of substrate to penetrate; pulse duration and mean, median, 
and maximum sound levels (dB re: 1 [micro]Pa): root mean square sound 
pressure level (SPLrms); cumulative sound exposure level (SELcum), peak 
sound pressure level (SPLpeak), and single-strike sound exposure level 
(SELs-s);
    [ssquf] For vibratory driving/removal and/or DTH excavation (DTH 
mono-hammer and cluster drill) (per pile): Duration of driving per 
pile; mean, median, and maximum sound levels (dB re: 1 [micro]Pa): root 
mean square sound pressure level (SPLrms), cumulative sound exposure 
level (SELcum) (and timeframe over which the sound is averaged);
    [ssquf] One-third octave band spectrum and power spectral density 
plot; and
    [ssquf] General Daily Site Conditions;
    [cir] Date and time of activities;
    [cir] Water conditions (e.g., sea state, tidal state); and
    [cir] Weather conditions (e.g., percent cover, visibility).

Reporting of Injured or Dead Marine Mammals

    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the Navy shall report the 
incident to NMFS Office of Protected Resources (OPR) 
([email protected]), NMFS (301-427-8401) and to the 
Greater Atlantic Region New England/Mid-Atlantic Stranding Coordinator 
(866-755-6622) as soon as feasible. The incident report must include 
the following information:
    [ssquf] Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);

[[Page 19537]]

    [ssquf] Species identification (if known) or description of the 
animal(s) involved;
    [ssquf] Condition of the animal(s) (including carcass condition if 
the animal is dead);
    [ssquf] Observed behaviors of the animal(s), if alive;
    [ssquf] If available, photographs or video footage of the 
animal(s); and
    [ssquf] General circumstances under which the animal was 
discovered.
    If the death or injury was clearly caused by the specified 
activity, the Navy must immediately cease the specified activities 
until NMFS OPR 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 this rule. The Navy shall not resume their 
activities until notified by NMFS that they can continue.

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 impacts or responses (e.g., intensity, duration), 
the context of any impacts or responses (e.g., critical reproductive 
time or location, foraging impacts affecting energetics), 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' 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 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 analysis 
applies to all the species listed in Table 3, 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, or groups of species, 
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.
    Construction 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 A and Level B harassment from underwater sounds generated by 
pile driving activities, rotary drilling, rock hammering, and DTH. 
Potential takes could occur if marine mammals are present in zones 
ensonified above the thresholds for Level A and Level B harassment, 
identified above, while activities are underway.
    The Navy's activities and associated impacts will occur within a 
limited, confined area of the stocks' range. Most of the work will 
occur behind the existing super flood basin walls that will act as a 
barrier to sound and will contain underwater noise to within a small 
portion of the Piscataqua River. The implementation of a soft start and 
a bubble curtain during some activities, along with other mitigation 
and monitoring measures already described, are expected to minimize the 
effects of the expected takes on the affected individuals. In addition, 
NMFS does not anticipate that serious injury or mortality will occur as 
a result of the Navy's construction activities given the nature of the 
activity, even in the absence of required mitigation.
    Exposures to elevated sound levels produced during pile driving and 
drilling may cause behavioral disturbance of some individuals. Effects 
on individuals that are taken by Level B harassment, as enumerated in 
the Estimated Take section, 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). Marine mammals within the Level B 
harassment zones may not show any visual cues they are disturbed by 
activities or they could become alert, avoid the area, leave the area, 
or display other mild responses that are not observable such as changes 
in vocalization patterns or increased haul out time (Thorson and Reyff, 
2006). Data from recent observations of harbor seals in the project 
area support the assumption that behavioral responses to the Navy's 
activities may be mild in nature (Navy, 2022). The Navy has observed 
116 harbor seals in the project since January 20, 2022. This includes 
observations at the conclusion of P-310 construction (January to 
February 2022) and the start of P-381 construction (May 2022 through 
October 16, 2022). Forty-eight of these observations occurred during 
periods with active construction, and the most common behavior recorded 
(n=28; 58.3 percent) was no response. The other common behaviors noted 
for these observations were swimming or milling (n=18; 37.5 percent), 
with notably lower observations of retreat/flush behaviors (n=1, 2.1 
percent) (Navy, 2022).
    Additionally, some of the species present in the region will only 
be present temporarily based on seasonal patterns or during transit 
between other habitats. These temporarily present species will be 
exposed to even smaller periods of noise-generating activity, further 
decreasing the impacts. Most likely, individual animals will simply 
move away from the sound source and be temporarily displaced from the 
area, although even this reaction has been observed primarily only in 
association with impact pile driving. The activities analyzed here are 
similar to numerous other construction activities conducted along both 
Atlantic and Pacific coasts, which have taken place with no known long-
term adverse consequences from behavioral harassment. These reactions 
and behavioral changes are expected to subside quickly when the 
exposures cease. The intensity of Level B harassment events will be 
minimized through use of mitigation measures described herein, 
including the soft starts and the use of the bubble curtain, which was 
not quantitatively factored into the take estimates. The Navy will use 
at least three PSOs stationed strategically to increase detectability 
of marine mammals during in-water construction activities and removal, 
enabling a high rate of success in implementation of shutdowns to avoid 
or minimize injury for most species. Further, given the absence of any 
major rookeries and only one isolated pinniped haulout site at Hicks 
Rocks approximately 2.4 km (1.5 mi) from the project area, we assume 
that takes by Level B harassment will have a negligible short-term 
effect on individuals and will not result in population-level impacts.
    Due to the levels and durations of likely exposure, animals that 
experience

[[Page 19538]]

PTS will likely only receive slight PTS, i.e., minor degradation of 
hearing capabilities within regions of hearing that align most 
completely with the frequency range of the energy produced by the 
Navy's activities (i.e., the low-frequency region below 2 kHz), not 
severe hearing impairment or impairment in the reigns of greatest 
hearing sensitivity. If hearing impairment does occur, it is most 
likely that the affected animal will lose a few dBs in its hearing 
sensitivity, which in most cases is not likely to meaningfully affect 
its ability to forage and communicate with conspecifics. Data do not 
suggest that a single instance in which an animal accrues PTS (or TTS) 
and is subject to behavioral disturbance would result in impacts to 
reproduction or survival. If PTS were to occur, it will be at a lower 
level likely to accrue to a relatively small portion of the population 
by being a stationary activity in one particular location.
    The project is also not expected to have significant adverse 
effects on any marine mammal habitat. The project activities will not 
modify existing marine mammal habitat since the project will occur 
within the same footprint as existing marine infrastructure. Impacts to 
the immediate substrate are anticipated, but these will be limited to 
minor, temporary suspension of sediments, which could impact water 
quality and visibility for a short amount of time, but which will not 
be expected to have any effects on individual marine mammals. The 
nearshore and intertidal habitat where the project will occur is an 
area of consistent vessel traffic from Navy and non-Navy vessels, and 
some local individuals will likely be somewhat habituated to the level 
of activity in the area, further reducing the likelihood of more severe 
impacts. The closest pinniped haulout used by harbor and gray seals is 
Hicks Rocks, located approximately 2.4 km (1.5 mi) away on the opposite 
side of the island and not within the ensonified area. There are no 
other biologically important areas for marine mammals near the project 
area.
    In addition, impacts to marine mammal prey species are expected to 
be minor and temporary. Overall, the area impacted by the project is 
very small compared to the available surrounding habitat, and does not 
include habitat of particular importance. The most likely impact to 
prey will be temporary behavioral avoidance of the immediate area. 
During construction activities, it is expected that some fish and 
marine mammals will temporarily leave the area of disturbance, thus 
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, the impacts to marine mammal habitat are 
not expected to cause significant or long-term negative consequences.
    In summary and as described above, the following factors primarily 
support our determination that the impacts resulting from this activity 
are not expected to adversely affect any of the species or stocks 
through effects on annual rates of recruitment or survival:
    [ssquf] No serious injury or mortality is anticipated or 
authorized;
    [ssquf] Level A harassment is expected to be of a lower degree that 
would not impact the fitness of any animals;
    [ssquf] Anticipated incidents of Level B harassment consist of, at 
worst, temporary modifications in behavior;
    [ssquf] The required mitigation measures (i.e., soft starts, bubble 
curtain, shutdown zones) are expected to be effective in reducing the 
effects of the specified activity;
    [ssquf] Minimal impacts to marine mammal habitat/prey are expected;
    [ssquf] There is one pinniped haulout in the vicinity of the 
project area (Hicks Rocks), but it is on the opposite side of Seavey 
Island and not within the ensonified area; and
    [ssquf] There are no known biologically important areas in the 
vicinity of the project.
    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 monitoring and mitigation 
measures, NMFS finds that the total marine mammal take from the Navy's 
activities will have a negligible impact on all affected marine mammal 
species or stocks.

Small Numbers

    As noted previously, only small numbers of incidental take may be 
authorized under sections 101(a)(5)(A) and (D) 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 amount of take NMFS has authorized is below one-
third of the estimated stock abundance for all five species (see Table 
16). The number of animals authorized to be taken from these stocks is 
considered small relative to the relevant stock's abundances even if 
each estimated take occurred to a new individual, which is an unlikely 
scenario.
    Based on the analysis contained herein of the Navy's activities 
(including the mitigation and monitoring measures) and the anticipated 
take of marine mammals, NMFS 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 will 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 
Navy construction activities will contain an adaptive management 
component. The reporting requirements associated with this 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 the Navy 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 will 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

[[Page 19539]]

number not authorized by these regulations or subsequent LOAs.

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 LOAs) with respect to potential 
impacts on the human environment.
    This action is consistent with categories of activities identified 
in Categorical Exclusion B4 (incidental take authorizations 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 determined that the action qualifies 
to be categorically excluded from further review under NEPA.

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 ensure 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 LOAs, 
NMFS consults internally whenever we propose to authorize take for 
endangered or threatened species.
    No incidental take of ESA-listed species is authorized 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.

Classification

    Pursuant to the procedures established to implement Executive Order 
12866, the Office of Management and Budget has determined that this 
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 
certified to the Chief Counsel for Advocacy of the Small Business 
Administration at the proposed rule stage that this action will not 
have a significant economic impact on a substantial number of small 
entities. The Navy is the sole entity that will be subject to the 
requirements in these regulations, and the Navy 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.
    This rule does not contain a collection-of-information requirement 
subject to the provisions of the Paperwork Reduction Act (PRA) because 
the applicant is a Federal agency.

Waiver of Delay in Effective Date

    The Assistant Administrator for Fisheries has determined that there 
is good cause under the Administrative Procedure Act (5 U.S.C 
553(d)(3)) to waive the 30-day delay in the effective date of the 
measures contained in the final rule. The Navy is the only entity 
subject to these regulations, and it has informed NMFS that it requests 
that this final rule take effect by April 1, 2023, when the IHA 
previously issued by NMFS to govern the taking of marine mammals 
incidental to U.S. Navy construction of the multifunctional expansion 
of Dry Dock 1 at Portsmouth Naval Shipyard, Kittery, Maine (87 FR 
19886, April 6, 2022) expires. Any delay in promulgating the final rule 
could result in a delay to the project schedule that would extend the 
completion of the project and cause further risks to the Navy Fleet 
boat schedule. In addition, in-water work at Dry Dock 1 is critical to 
timely completion of the overall project. Delaying the completion of 
ongoing work will have increased risk on other mission critical work, 
as some of the construction components cannot begin until others are 
started or in some cases completed. Moreover, the contractor is onsite 
and currently working under an existing IHA (87 FR 19886, April 6, 
2022), therefore, the Navy is ready to operate under the LOA 
immediately. For these reasons, the Assistant Administrator finds good 
cause to waive the 30-day delay in the effective date. In addition, the 
rule allows authorization of incidental take of marine mammals that 
would otherwise be prohibited under the statute. Therefore, by granting 
an exception to the Navy, the rule will relieve restrictions under the 
MMPA, which provides a separate basis for waiving the 30-day effective 
date for the rule.

List of Subjects in 50 CFR Part 217

    Exports, Fish, Imports, Indians, Labeling, Marine mammals, 
Penalties, Reporting and recordkeeping requirements, Seafood, 
Transportation.

Samuel D. Rauch, III,
Deputy Assistant Administrator for Regulatory Programs, National Marine 
Fisheries Service.

    For reasons set forth in the preamble, NMFS amends 50 CFR part 217 
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 N to part 217 to read as follows:

Subpart N--Taking and Importing Marine Mammals Incidental to U.S. 
Navy Construction at Portsmouth Naval Shipyard, Kittery, Maine.

Sec.
217.130 Specified activity and geographical region.
217.131 Effective dates.
217.132 Permissible methods of taking.
217.133 Prohibitions.
217.134 Mitigation requirements.
217.135 Requirements for monitoring and reporting.
217.136 Letters of Authorization.
217.137 Renewals and modifications of Letters of Authorization.
217.138 [Reserved]
217.139 [Reserved]


Sec.  217.130  Specified activity and geographical region.

    (a) Regulations in this subpart apply only to taking of marine 
mammals by the U.S. Navy (Navy) and those persons it authorizes or 
funds to conduct activities that occur incidental to construction 
activities related to the multifunctional expansion and modification of 
Dry Dock 1 in the areas outlined in paragraph (b) of this section.
    (b) The taking of marine mammals by the Navy may be authorized in a 
Letter of Authorization (LOA) only if it occurs at Portsmouth Naval 
Shipyard, Kittery, Maine.


Sec.  217.131  Effective dates.

    Regulations in this subpart are effective for a period of 5 years 
from the date of issuance.


Sec.  217.132  Permissible methods of taking.

    Under an LOA issued pursuant to Sec.  216.106 of this chapter and 
Sec.  217.136, the Holder of the LOA (hereinafter ``Navy'') may 
incidentally, but not intentionally, take marine mammals within the 
area described in

[[Page 19540]]

Sec.  217.130(b) by harassment associated with construction activities 
related to the multifunctional expansion and modification of Dry Dock 
1, provided the activity is in compliance with all terms, conditions, 
and requirements of the regulations in this subpart and the applicable 
LOA.


Sec.  217.133  Prohibitions.

    (a) Except for the takings contemplated in Sec.  217.132 and 
authorized by a LOA issued under Sec.  216.106 of this chapter and 
Sec.  217.136, it is unlawful for any person to do any of the following 
in connection with the activities described in Sec.  217.130:
    (1) Violate, or fail to comply with, the terms, conditions, and 
requirements of this subpart or a LOA issued under Sec.  216.106 of 
this chapter and Sec.  217.136;
    (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 after 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.  217.134  Mitigation requirements.

    (a) When conducting the activities identified in Sec.  217.130(a), 
the mitigation measures contained in this subpart and any LOA issued 
under Sec.  216.106 of this chapter and Sec.  217.136 must be 
implemented. These mitigation measures include:
    (1) A copy of any issued LOA must be in the possession of the Navy, 
its designees, and work crew personnel operating under the authority of 
the issued LOA at all times that activities subject to this LOA are 
being conducted.
    (2) Should environmental conditions deteriorate such that marine 
mammals within the entire shutdown zone would not be visible (e.g., 
fog, heavy rain, night), the Navy shall delay pile driving and drilling 
until observers are confident marine mammals within the shutdown zone 
could be detected.
    (3) The Navy must ensure that construction supervisors and crews, 
the monitoring team, and relevant Navy staff are trained prior to the 
start of construction activity subject to this rule, so that 
responsibilities, communication procedures, monitoring protocols, and 
operational procedures are clearly understood. New personnel joining 
during the project will be trained prior to commencing work.
    (4) The Navy, construction supervisors and crews, protected species 
observers (PSOs), and relevant Navy staff must avoid direct physical 
interaction with marine mammals during construction activity. If a 
marine mammal comes within 10 m of such activity, operations will cease 
and vessels will reduce speed to the minimum level required to maintain 
steerage and safe working conditions, as necessary, to avoid direct 
physical interaction.
    (5) The Navy must monitor the project area to the maximum extent 
possible based on the required number of PSOs, required monitoring 
locations, and environmental conditions as described in this rule and 
the NMFS-approved Marine Mammal Monitoring Plan.
    (6) Monitoring must take place from 30 minutes prior to initiation 
of pile driving or drilling activity (i.e., pre-start clearance 
monitoring) through 30 minutes post-completion of pile driving or 
drilling activity.
    (7) For all pile driving and drilling activities, the Navy must 
implement shutdown zones with radial distances as identified in a LOA 
issued under Sec.  216.106 of this chapter and Sec.  217.136. If a 
marine mammal comes within or approaches the shutdown zone, such 
operations must cease.
    (8) In the event of a delay or shutdown of activity resulting from 
marine mammals in the shutdown zone, animals must be allowed to remain 
in the shutdown zone (i.e., must leave of their own volition) and their 
behavior must be monitored and documented. If a marine mammal is 
observed within the shutdown zone, pile driving or drilling activities 
may not commence or resume until at least one of the following 
conditions has been met:
    (i) The animal has been observed exiting the shutdown zone;
    (ii) The animal is thought to have exited the shutdown zone based 
on a determination of its course, speed, and movement relative to the 
pile driving location; or
    (iii) The shutdown zone has been clear from any additional 
sightings for fifteen minutes.
    (9) If pile driving or drilling construction activities cease for 
more than 30 minutes, the pre-activity monitoring of the shutdown zone 
must commence.
    (10) The Navy must conduct monitoring to include the entire region 
of influence, which includes the area within the Level A and Level B 
harassment zones with radial distances as identified in a LOA issued 
under Sec.  216.106 of this chapter and Sec.  217.136.
    (11) The Navy must use soft start techniques when impact pile 
driving. Soft start requires contractors to provide an initial set of 
strikes from the hammer at reduced energy, followed by a 30-second 
waiting period, then two subsequent reduced-energy strike sets. A 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.
    (12) The Navy must install a bubble curtain across the entrance 
openings during DTH cluster drill and hydraulic rock hammering 
activities. The bubble curtain must adhere to the following 
restrictions:
    (i) The bubble curtain must distribute air bubbles across 100 
percent of the entrance openings for the full depth of the water 
column;
    (ii) The lowest bubble ring must be in contact with the substrate 
for the full extent of the curtain, and the weights attached to the 
bottom of the curtain must ensure 100 percent substrate contact. No 
parts of the curtain or other objects shall prevent full substrate 
contact; and
    (iii) Air flow to the bubblers must be balanced across the entrance 
openings to the super flood basin.
    (iv) The Navy 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 in-water 
construction activities.
    (13) The bubble curtain may be discontinued for certain activities 
should the results of hydroacoustic recordings inside the bubble 
curtain show that the source levels from those activities do not result 
in the Level A harassment thresholds being achieved across the entire 
region of influence, upon review of the data by NMFS.
    (14) Pile driving and drilling activity must be halted upon 
observation of either a species entering or within the harassment zone 
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.
    (b) [Reserved]


Sec.  217.135  Requirements for monitoring and reporting.

    (a) Marine Mammal monitoring must be conducted in accordance with 
the conditions in this section and the Marine Mammal Monitoring Plan. 
The Navy must submit a Marine Mammal

[[Page 19541]]

Monitoring Plan to NMFS for approval in advance of construction.
    (b) Monitoring must be conducted by qualified PSOs in accordance 
with the following conditions:
    (1) PSOs must be independent (i.e., not construction personnel) and 
have no other assigned tasks during monitoring periods.
    (2) 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.
    (3) Other PSOs may substitute relevant experience, education 
(degree in biological science or related field), or training for prior 
experience performing the duties of a PSO during construction activity 
pursuant to a NMFS-issued incidental take authorization.
    (4) Where a team of three PSOs are required, a lead observer or 
monitoring coordinator shall be designated. The lead observer must have 
prior experience performing the duties of a PSO during construction 
activity pursuant to a NMFS-issued incidental take authorization; and
    (5) One PSO must be designated as lead PSO or monitoring 
coordinator. The lead PSO must have prior experience performing the 
duties of a PSO during construction activity pursuant to a NMFS-issued 
incidental take authorization.
    (6) PSOs must work in shifts to reduce fatigue and ensure their 
ability to monitor for marine mammals.
    (7) PSOs must be approved by NMFS prior to beginning any activity 
subject to this LOA.
    (c) For all pile driving activities, a minimum of three PSOs must 
be stationed on boats, docks, or piers sufficient to monitor the 
harassment and shutdown zones, and as described in the Marine Mammal 
Monitoring Plan.
    (d) PSOs must record all observations of marine mammals, regardless 
of distance from the pile/hole being driven/drilled or the construction 
activity taking place (i.e., DTH, rotary drilling, rock hammering), as 
well as additional data indicated in the reporting requirements.
    (e) The Navy must conduct hydroacoustic data collection (sound 
source verification and propagation loss) as described in a LOA and in 
accordance with a hydroacoustic monitoring plan that must be approved 
by NMFS in advance of construction. This plan shall include acoustic 
monitoring inside the bubble curtain to measure construction generated 
noise levels.
    (f) The harassment and/or shutdown zones may be modified with NMFS' 
approval following NMFS' acceptance of an acoustic monitoring report.
    (g) The Navy must submit a draft monitoring report to NMFS within 
90 work days of the completion of required monitoring for each portion 
of the project as well as a comprehensive summary report at the end of 
the project. The reports will detail the monitoring protocol and 
summarize the data recorded during monitoring. Final annual reports 
(each portion of the project and comprehensive) must be prepared and 
submitted within 30 days following resolution of any NMFS comments on 
the draft report. If no comments are received from NMFS within 30 days 
of receipt of the draft report, the report must be considered final. If 
comments are received, a final report addressing NMFS comments must be 
submitted within 30 days after receipt of comments.
    (h) All draft and final monitoring reports must be submitted to 
[email protected] and [email protected].
    (i) The reports must at minimum contain the informational elements 
described as follows (as well as any additional information described 
in the Marine Mammal Monitoring Plan), including:
    (1) Dates and times (begin and end) of all marine mammal 
monitoring.
    (2) Construction activities occurring during each daily observation 
period, including:
    (i) The number and type of piles that were driven or removed and by 
what method (i.e., impact, vibratory, DTH, rotary drilling, rock 
hammering.
    (ii) The total duration of driving time for each pile/hole 
(vibratory driving, rotary drilling) and number of strikes for each 
pile/hole (impact driving, hydraulic rock hammering).
    (iii) For DTH, the duration of operation for both impulsive and 
non-pulse components as well as the strike rate.
    (3) PSO locations during marine mammal monitoring.
    (4) 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);
    (5) Upon observation of a marine mammal, the following information:
    (i) Name of PSO who sighted the animal(s) and PSO location, as well 
as the activity at the time of the sighting;
    (ii) Time of sighting;
    (iii) Identification of the animal (e.g., genus/species, lowest 
possible taxonomic level, or unidentified), PSO confidence in 
identification, and the composition of the group if there is a mix of 
species;
    (iv) Distances and bearings of each marine mammal observed in 
relation to the pile being driven or drilled for each sighting (if pile 
driving or drilling was occurring at time of sighting).
    (v) Estimated number of animals (min/max/best estimate);
    (vi) Estimated number of animals by cohort (adults, juveniles, 
neonates, group composition, etc.);
    (vii) Animal's closest point of approach and estimated time spent 
within the harassment zone;
    (viii) Description of any marine mammal behavioral observations 
(e.g., observed behaviors such as feeding or traveling), including an 
assessment of behavioral responses to the activity (e.g., no response 
or changes in behavioral state such as ceasing feeding, changing 
direction, flushing, or breaching);
    (6) Number of marine mammals detected within the harassment zones, 
by species;
    (7) Detailed information about any implementation of any mitigation 
(e.g., shutdowns and delays), a description of specific actions that 
ensued, and resulting changes in the behavior of the animal, if any; 
and
    (j) The Holder will submit all PSO datasheets and/or raw sightings 
data with the draft reports.
    (k) The Navy must report the hydroacoustic data collected as 
required by a LOA issued under Sec.  216.106 of this chapter and Sec.  
217.136 and as described in the Acoustic Monitoring Plan, which at a 
minimum, must include:
    (1) Hydrophone equipment and methods: recording device, sampling 
rate, distance (m) from the pile where recordings were made; depth of 
water and recording device(s);
    (2) Type and size of pile being driven, substrate type, method of 
driving during recordings (e.g., hammer model and energy), and total 
pile driving duration;
    (3) Whether a sound attenuation device is used and, if so, a 
detailed description of the device used and the duration of its use per 
pile;
    (4) For impact pile driving and/or DTH excavation (DTH mono-hammer 
and cluster drill) (per pile/hole): Number of strikes and strike rate; 
depth of substrate to penetrate; pulse duration and mean, median, and 
maximum sound levels (dB re: 1 [micro]Pa): root mean square sound 
pressure level (SPLrms); cumulative sound exposure level (SELcum), peak 
sound pressure level

[[Page 19542]]

(SPLpeak), and single-strike sound exposure level (SELss);
    (5) For vibratory driving/removal, rotary drilling, and/or DTH 
excavation (DTH mono-hammer and cluster drill) (per pile/hole): 
Duration of driving per pile; mean, median, and maximum sound levels 
(dB re: 1 [micro]Pa): root mean square sound pressure level (SPLrms), 
cumulative sound exposure level (SELcum) (and timeframe over which the 
sound is averaged);
    (6) One-third octave band spectrum and power spectral density plot; 
and
    (7) General Daily Site Conditions, including the date and time of 
activities, and environmental data such as wind speed and direction, 
air temperature, humidity, surface water temperature, tidal state, 
water depth, wave height, weather conditions, and other factors that 
could contribute to influencing the airborne and underwater sound 
levels (e.g., aircraft, boats, etc.).
    (l) In the event that personnel involved in the construction 
activities discover an injured or dead marine mammal, the Navy must 
report incident to the Office of Protected Resources (OPR), NMFS 
([email protected] and [email protected]) and to 
the Greater Atlantic Region New England/Mid-Atlantic Regional Stranding 
Coordinator (978-282-8478 or 978-281-9291) as soon as feasible. If the 
death or injury was clearly caused by the specified activity, the Navy 
must immediately cease the specified activities until NMFS OPR 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 this rule and the LOA issued under Sec.  216.106 of this chapter and 
Sec.  217.136. The Navy will 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.  217.136  Letters of Authorization.

    (a) To incidentally take marine mammals pursuant to this subpart, 
the Navy 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 these regulations.
    (c) If an LOA expires prior to the expiration date of these 
regulations, the Navy 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, the Navy must 
apply for and obtain a modification of the LOA as described in Sec.  
217.137.
    (e) The LOA will 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 will be based on a determination that the 
level of taking will be consistent with the findings made for the total 
taking allowable under these regulations.
    (g) Notice of issuance or denial of an LOA will be published in the 
Federal Register within 30 days of a determination.


Sec.  217.137  Renewals and modifications of Letters of Authorization.

    (a) An LOA issued under Sec.  216.106 of this chapter and Sec.  
217.136 for the activity identified in Sec.  217.130(a) may 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 these regulations; and
    (2) NMFS determines that the mitigation, monitoring, and reporting 
measures required by the previous LOA under these regulations 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 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) A LOA issued under Sec.  216.106 of this chapter and Sec.  
217.136 for the activity identified in Sec.  217.130(a) may be modified 
by NMFS under the following circumstances:
    (1) NMFS may modify (including augment) the existing mitigation, 
monitoring, or reporting measures (after consulting with Navy 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 preamble for these 
regulations;
    (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 Navy's monitoring from previous years;
    (B) Results from other marine mammal and/or sound research or 
studies; and
    (C) Any information that reveals marine mammals may have been taken 
in a manner, extent or number not authorized by these regulations or 
subsequent LOAs; and
    (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.  216.106 of this 
chapter and Sec.  217.136, a LOA may be modified without prior public 
notice or opportunity for public comment. Notification would be 
published in the Federal Register within 30 days of the action.


Sec.  217.138-217.139  [Reserved]

[FR Doc. 2023-06300 Filed 3-30-23; 8:45 am]
BILLING CODE 3510-22-P