Takes of Marine Mammals During Specified Activities; Confined Blasting Operations by the U.S. Army Corps of Engineers During the Port of Miami Construction Project in Miami, Florida, 6545-6567 [2014-02281]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 79, Number 23 (Tuesday, February 4, 2014)]
[Notices]
[Pages 6545-6567]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-02281]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XD001


Takes of Marine Mammals During Specified Activities; Confined 
Blasting Operations by the U.S. Army Corps of Engineers During the Port 
of Miami Construction Project in Miami, Florida

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

ACTION: Notice; proposed Incidental Harassment Authorization; request 
for comments.

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SUMMARY: NMFS has received an application from the U.S. Army Corps of 
Engineers (ACOE) for an Incidental Harassment Authorization (IHA) to 
take small numbers of marine mammals, by Level B harassment, incidental 
to confined blasting operations in the Port of Miami in Miami, Florida. 
NMFS has reviewed the application, including all supporting documents, 
and determined that it is adequate and complete. Pursuant to the Marine 
Mammal Protection Act (MMPA), NMFS is requesting comments on the its 
proposal to issue an IHA to ACOE to incidentally harass, by Level B 
harassment only, marine mammals during the specified activity.

DATES: Comments and information must be received no later than March 6, 
2014.

ADDRESSES: Comments on the application should be addressed to P. 
Michael Payne, Chief, Permits and Conservation Division, Office of 
Protected Resources, National Marine

[[Page 6546]]

Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910. The 
mailbox address for providing email comments is ITP.Goldstein@noaa.gov. 
NMFS is not responsible for email comments sent to addresses other than 
the one provided here. Comments sent via email, including all 
attachments, must not exceed a 10-megabyte file size.
    All comments received are a part of the public record and will 
generally be posted to https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications without change. All Personal Identifying 
Information (for example, name, address, etc.) voluntarily submitted by 
the commenter may be publicly accessible. Do not submit confidential 
business information or otherwise sensitive or protected information.
    A copy of the application containing a list of the references used 
in this document may be obtained by writing to the above address, 
telephoning the contact listed here (see FOR FURTHER INFORMATION 
CONTACT) or visiting the internet at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.
    This project was previously evaluated by the ACOE under an 
Environmental Impact Statement (EIS) and a Record of Decision (ROD) for 
the project was signed on May 22, 2006, which is also available at the 
same internet address. Documents cited in this notice may be viewed, by 
appointment, during regular business hours, at the aforementioned 
address.

FOR FURTHER INFORMATION CONTACT: Howard Goldstein or Jolie Harrison, 
Office of Protected Resources, NMFS, 301-427-8401.

SUPPLEMENTARY INFORMATION:

Background

    Section 101(a)(5)(D) of the MMPA (16 U.S.C. 1361(a)(5)(D)) directs 
the Secretary of Commerce (Secretary) to allow, upon request, the 
incidental, but not intentional, taking of small numbers of marine 
mammals of a species or population stock, by United States citizens who 
engage in a specified activity (other than commercial fishing) within a 
specified geographical region if certain findings are made and, if the 
taking is limited to harassment, a notice of a proposed authorization 
is provided to the public for review.
    Authorization for the incidental taking of small numbers of marine 
mammals 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 subsistence uses (where relevant). The authorization must 
set forth the permissible methods of taking, other means of effecting 
the least practicable adverse impact on the species or stock and its 
habitat, and requirements pertaining to the mitigation, monitoring and 
reporting of such takings. NMFS has defined ``negligible impact'' in 50 
CFR 216.103 as ``. . . an impact resulting from the specified activity 
that cannot be reasonably expected to, and is not reasonably likely to, 
adversely affect the species or stock through effects on annual rates 
of recruitment or survival.''
    Section 101(a)(5)(D) of the MMPA established an expedited process 
by which citizens of the United States can apply for an authorization 
to incidentally take small numbers of marine mammals by harassment. 
Section 101(a)(5)(D) of the MMPA establishes a 45-day time limit for 
NMFS' review of an application followed by a 30-day public notice and 
comment period on any proposed authorizations for the incidental 
harassment of small number of marine mammals. Within 45 days of the 
close of the public comment period, NMFS must either issue or deny the 
authorization.
    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as:

any act of pursuit, torment, or annoyance which (I) has the 
potential to injure a marine mammal or marine mammal stock in the 
wild [Level A harassment]; or (ii) has the potential to disturb a 
marine mammal or marine mammal stock in the wild by causing 
disruption of behavioral patterns, including, but not limited to, 
migration, breathing, nursing, breeding, feeding, or sheltering 
[Level B harassment].

16 U.S.C. 1362(18).

Summary of Request

    On November 15, 2013, NMFS received a letter from the ACOE, 
requesting an IHA. The requested IHA would authorize the take, by Level 
B (behavioral) harassment, of small numbers of Atlantic bottlenose 
dolphins (Tursiops truncatus) incidental to confined blasting 
operations in the Miami Harbor, Port of Miami, in Miami-Dade County, 
Florida. The IHA application was considered adequate and complete on 
November 26, 2013. NMFS issued an IHA to the ACOE on July 31, 2012 (77 
FR 49278, August 15, 2012) for the same activities from March 15, 2013 
to March 14, 2014 and the ACOE complied with the mitigation and 
monitoring requirements in the IHA. The ACOE plans to conduct four 
components as part of the project in Miami Harbor (see Figure 1 of the 
ACOE's IHA application for a map and more details). These components 
are:
    (1) Widening of Cut 1 and deepening of Cut 1 and Cut 2;
    (2) Adding a turn widener and deepening at the southern 
intersection of Cut 3 within Fisherman's Channel;
    (3) Widening and deepening the Fisher Island Turning Basin; and
    (4) Expanding the Federal Channel and Port of Miami berthing areas 
in Fisherman's Channel and the Lummus Island Turning Basin.
    The construction would likely be completed using a combination of 
mechanical dredge (i.e., a clamshell or backhoe), cutterhead dredge, 
and rock pre-treatment by confined blasting. The dredging would remove 
approximately 5,000,000 cubic yards (3,822,774.3 cubic meters [m\3\]) 
of material from the harbor. Material removed from the dredging would 
be placed in Miami Harbor Ocean Dredged Material Disposal Site, or used 
to construct seagrass and reef mitigation projects.
    The confined blasting is planned to take place beginning during the 
spring of 2014 (March 2014), and is expected to take up to 24 months in 
Miami, Florida. Additional information on the construction project is 
contained in the application, which is available upon request (see 
ADDRESSES). Confined blasting means that the shots would be 
``confined'' in the rock with stemming that prevents the explosive 
energy from going upward from the hole into the water column, and 
forces it to go laterally into the surrounding rock. In confined 
blasting, each charge is placed in a hole drilled in the rock 
approximately 5 to 10 feet (ft) (1.5 to 3.1 meters [m]) deep; depending 
on how much rock needs to be broken and the intended project depth. The 
hole is then capped with an inert material, such as crushed rock. A 
charge is the total weight of the explosives to be detonated during a 
blast. This can also be broken down into the weight of the individual 
delays. This process is referred to as ``stemming the hole'' (see 
Figure 6 and 7 of the ACOE's application).

Description of the Proposed Specified Activities

    The ACOE proposes to deepen and widen the Federal channels at Miami 
Harbor, Port of Miami, in Miami-Dade County, Florida. The recommended 
plan (Alternative 2 of the Environmental Impact Statement [EIS]) 
includes four components:
    (1) Widen the seaward portion of Cut 1 from 500 to 800 ft (152.4 to 
243.8 m) and deepen Cut 1 and Cut 2 from a project depth of -44 to -52 
ft (13.4 to 15.9 m);

[[Page 6547]]

    (2) Add a turn widener at the southern intersection of Cut 3 within 
Fisherman's Channel and deepen to a project depth of -50 ft (-15.2 m);
    (3) Increase the Fisher Island Turning Basin from 1,200 to 1,500 ft 
(365.8 to 457.2 m), truncate the northeast section of the turning basin 
to minimize seagrass impacts, and deepen from -42 ft (-12.8 m) to a 
project depth of -50 ft; and
    (4) Expand the Federal Channel and Port of Miami berthing areas in 
Fisherman's Channel and in the eastern end of the Lummus Island Turning 
Basin (LITB) by 60 ft (18.3 m) to the south for a total of a 160 ft 
(48.8 m) wide berthing area and would be deepened from -42 ft to a 
project depth of -50 ft. The Federal Channel would be widened 40 ft 
(12.2 m) to the south, for a 100 ft (30.5 m) total width increase in 
Fisherman's Channel. This component (referred to as Component 5 in the 
ACOE's IHA application) would deepen Fisherman's Channel and the LITB 
from -42 ft to a project depth of -50 ft. See Figure 1 of ACOE's IHA 
application for a map of the proposed project's components.
    Disposal of the estimated five million cubic yards of dredged 
material would occur at up to three disposal sites (seagrass mitigation 
area, offshore artificial reef mitigation areas, and the Miami Offshore 
Dredged Material Disposal Site). This project was previously evaluated 
under an Environmental Impact Statement (EIS) titled ``Miami Harbor 
Miami-Dade County, Florida Navigation Study, Final General Reevaluation 
Report and Environmental Impact Statement,'' prepared under the 
National Environmental Policy Act, and a Record of Decision for the 
project was signed on May 22, 2006. The original proposed project 
included six components, two of which (components four and six) have 
been removed. The EIS provides a detailed explanation of project 
location as well as all aspects of project implementation. It is also 
available online for public review at: https://www.saj.usace.army.mil/Divisions/Planning/Branches/Environmental/DOCS/OnLine/Dade/MiamiHarbor/NAV_STUDY_VOL-1_MIAMI.pdf.
    To achieve the deepening of the Miami Harbor from the existing 
depth of -45 ft (-13.7 m) to project depth of -52 ft, pretreatment of 
some of the rock areas may be required using confined underwater 
blasting, where standard construction methods are unsuccessful due to 
the hardness of the rock. The ACOE has used two criteria to determine 
which areas are most likely to need confined blasting for the Miami 
Harbor expansion: (1) areas documented by core borings to contain hard 
and/or massive rock; and (2) areas previously blasted in the harbor 
during the 2005 confined blasting and dredging project.
    The duration of the confined blasting is dependent upon a number of 
factors including hardness of rock, how close the drill holes are 
placed, and the type of dredging equipment that would be used to remove 
the pretreated rock. Without this information, an exact estimate of how 
many confined ``blast days'' would be required for the project cannot 
be determined. The harbor deepening project at Miami Harbor in 2005 to 
2006 estimated between 200 to 250 days of confined blasting with one 
shot per day (a blast day) to pre-treat the rock associated with that 
project; however, the contractor completed the project in 38 days with 
40 confined blasts. A shot, or blast, is an explosion made up of a 
group of blast holes set in a pattern referred to as a blast array that 
are detonated all at once or in a staggered manner with delays between 
them. A blast hole is the hole drilled into the bottom substrate that 
would be filled with explosives, capped with stemming, and detonated.
    The upcoming expansion at Miami Harbor estimates a maximum of 600 
blast days for the entire multi-year project footprint. The ACOE 
estimates a maximum number of 313 blast days for the duration of this 
IHA (i.e., 365 days in a year minus 52 Sundays [no confined blasting is 
allowed on Sundays due to local ordinances]). A blast day is defined as 
one confined blast event/day. A blast event is made up of all the 
actions during a shot, this includes the Notice of Project Team and 
Local Authorities, which occurs two hours before the blast is 
detonated, through the end of the protected species watch, which last 
30 minutes after the blast detonation. A typical blast timeline 
consists of: Notice to Project Team and Local Authorities (T minus 2 
hours), protected species watch begins (T minus 1 hour), Notice to 
Mariners (channel closes, T minus 15 minutes), fish scare (T minus 1 
minute), blast detonation, all clear signal (T plus 5 minutes), 
protected species watch ends (T plus 30 minutes), and delay capsule--if 
an animal is observed in either the danger or safety zones, the blast 
is delayed to monitor the animal until it leaves, on its own volition, 
from both the danger and safety zones (can occur between T minus 1 hour 
and detonation). There may be more than one confined blast event in a 
calendar day. While confined blasting events would occur only during 
daylight hours, typically six days a week. Other operations associated 
with the action (i.e., dredging activities) would take place 24 hours a 
day, typically seven days a week. Confined blasting activities normally 
would not take place on Sundays due to local ordinances. The contractor 
may drill the blast array (i.e., to physically drill the holes in the 
substrate to be removed in the pattern designed by the blasting 
engineer to remove the rock in the manner he/she needs to achieve the 
needed results) at night and then blast after at least two hours after 
sunrise (1 hour, plus one hour of monitoring). After detonation of the 
first explosive array, a second array may be drilled and detonated 
before the one-hour before sunset prohibition is triggered. An 
explosive array is the pattern of blast holes drilled into the bottom 
substrate that would be fractured by the blast detonation.
    In May 2013, the ACOE awarded the contract to the Great Lakes Dock 
and Dredge Company, the firm that completed the previous blasting and 
dredging at Miami Harbor in 2005 to 2006. The current contract was 
split into three portions, a base bid, which includes the Outer 
Entrance Channel (Cuts 1 and 2 in Figure 1) as well as construction of 
the artificial reefs and seagrass mitigation areas; Option A includes 
Fisherman's Channel and the Inner Entrance Channel inside the jetties, 
as well as the Port of Miami's berthing areas and Option B includes the 
Fisher Island Turning Basin (Cut 3). Although a contractor has been 
selected, per the contract specifications, the contractor does not have 
to prepare the contractor-developed confined blasting plan no less than 
30 days prior to blasting activities begin. This plan specifically 
identifies the number of holes that would be drilled, the amount of 
explosives that would be used for each hole, the number of confined 
blasts per day (usually no more than two per a day) or the number of 
days the construction is anticipated to take to complete. Although the 
blasting plan has not been provided to the ACOE, the contractor has 
identified a more specific timeframe for the blasting to occur. 
Blasting in the base bid would be conducted between March and June 
2014. Because Options A and B have not been exercised, the blasting in 
these areas has not been scheduled. The ACOE is required to have all 
authorizations and permits completed (including the possession of an 
IHA) prior to the request for proposal and advertising the contract, 
per the Competition in Contracting Act, and the Federal Acquisition 
Regulations. When possible, the ACOE has made reasonable

[[Page 6548]]

estimates of the bounds based on previous similar projects that have 
been conducted by the ACOE here and at other locations. NMFS supports 
the ACOE's use of the worst-case scenarios to estimate confined 
blasting activities and associated potential impacts.
    Drill holes are small in diameter (typically 2 to 4 in [5.1 to 10.2 
cm] in diameter) and only 5 to 10 ft (1.5 to 3.1 m) deep, drilling 
activities take place for a short time duration, with no more than 
three holes being drilled at the same time (based on the current drill-
rigs available in the industry that range from one to three drills). 
During the 2005 confined blasting event, dolphins were seen near the 
drill barge during drilling events and the ACOE did not observe 
avoidance behavior. No measurements associated with noise from drilling 
small blast holes have been recorded. The ACOE does not expect 
incidental harassment from drilling operations and is not requesting 
take associated with this activity. The ACOE is collecting data 
regarding noise from drilling activities associated with confined 
blasting activities in an effort to increase the available knowledge 
concerning confined underwater blasting and all its related component 
elements.
    Although the ACOE does not have a specific contractor-provided 
confined blasting plan, the ACOE developed plans and specifications for 
the project that direct the contractor to do certain things in certain 
ways and are basing these plans and specifications on the previous 
deepening project in Miami Harbor (construction was conducted in 2005 
to 2006).
    The previous ACOE project in Miami Harbor required a maximum weight 
of explosives used in each delay of 376 pounds (lb) (170.6 kilograms 
[kg]) and the contractors blasted once or twice daily from June 25 to 
August 25, 2005, for a total of 40 individual blasts in 38 days of 
confined blasting. The 2005 project, which utilized confined blasting, 
was limited to Fisherman's Channel and the Dodge-Lummus Island Turning 
Basin (see Figure 2 of ACOE's IHA application, which shows the confined 
blasting footprint for the 2005 project), whereas the project described 
in the ACOE's application includes Fisherman's Channel, Dodge-Lummus 
Island Turning Basin, Fisher Island Turning Basin, and Inner and Outer 
Entrance Channel. This larger area would result in more confined 
blasting for this project than was completed in 2005, as it includes 
areas not previously blasted in 2005.
    A copy of the Federal Register notice of issuance for the IHA from 
2003 (68 FR 32016, May 29, 2003), the IHA renewal from 2005 (70 FR 
21174, April 25, 2005), and the final biological monitoring report from 
the ACOE's Miami Harbor Phase II project (completed in 2006) was 
provided as part of the ACOE's 2012 application (and attached to the 
current application) and available on NMFS's Web site at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm#iha. For the new 
construction at Miami Harbor, the ACOE expects the project may take up 
to two calendar years (March 2014 through June 2015), and the ACOE 
would seek subsequent renewals of this IHA after issuance, with 
sufficient time to prevent any delay to the project.
    For the proposed deepening at Miami Harbor, the ACOE has consulted 
with blasting industry experts and believes, based on the rock hardness 
and composition at Miami Harbor, a maximum charge weight per delay of 
450 lbs (204.1 kg) should be expected. The minimum charge weight would 
be 10 lbs (4.5 kg). A delay is a period of time (in milliseconds) 
between small detonations that are part of the total charge weight of 
the entire detonation.
    The focus of the confined blasting work at the Miami Harbor is to 
pre-treat the massive limestone formation that makes up the base of 
Miami Harbor prior to removal by a dredge utilizing confined blasting, 
meaning the explosive shots would be ``confined'' in the rock. 
Typically, each blast array is set up in a square or rectangle area 
divided into rows and columns (see Figures 3, 4, and 5 in the ACOE's 
IHA application). A typical blast array is 10 holes long by 4 holes 
wide with holes being spaced 40 ft (12.2 m) apart covering an area of 
4,000 ft\2\ (371.6 m\2\). Blast arrays near bulkheads can be long-
linear feature of one-hole wide by 8 or 10 holes long (see Figure 4 of 
the IHA application).
    In confined blasting, each charge is placed in a hole drilled in 
the rock approximately 5 to 10 ft (1.5 to 3.0 m) deep; depending on how 
much rock needs to be broken and the intended project depth. The hole 
is then capped with an inert material, such as crushed rock. This 
process is referred to as ``stemming the hole'' (see Figure 6 and 7 of 
ACOE's IHA application; each bag as shown contains approximate volume 
of material used per discharge). The ACOE used this technique 
previously at the Miami Harbor Phase II project in 2005. NMFS issued an 
IHA for that operation on May 22, 2003 (68 FR 32016, May 29, 2003) and 
renewed the IHA on April 19, 2005 (70 FR 21174, April 25, 2005).
    For the Port of Miami expansion project (Miami Harbor Phase II) 
that used confined blasting as a pre-treatment technique, the stemming 
material was angular crushed rock. (Stemming is the process of filling 
each borehole with crushed rock after the explosive charge has been 
placed. After the blasting charge has been set, then the chain of 
explosives within the rock is detonated. A chain of explosives refers 
to all of the detonations within the blast array, without regard to how 
many holes are in the array. They would detonate within milliseconds of 
each other. Stemming reduces the strength of the outward pressure wave 
produced by blasts.) The optimum size of stemming material is material 
that has an average diameter of approximately 0.05 times the diameter 
of the blast-hole. The selected material must be angular to perform 
properly (Konya, 2003). For the ACOE's project, specifications have 
been prepared by the geotechnical branch of the Jacksonville District 
and are the same as those completed during the Miami Harbor Phase II 
project.
    The specifications for any construction utilizing the confined 
blasting for the deepening of Miami Harbor would have similar stemming 
requirements as those that were used for the Miami Harbor Phase II 
project in 2005 to 2006. The length of stemming material would vary 
based on the length of the hole drilled, however a minimum of two 2-ft 
(0.6 m) walls would be included in the project specific specifications. 
Studies have shown that stemmed blasts have up to a 60 to 90 percent 
decrease in the strength of the pressure wave released, compared to 
open water blasts of the same charge weight (Nedwell and 
Thandavamoorthy, 1992; Hempen et al., 2005; Hempen et al., 2007). 
However, unlike open water (unconfined) blasts (see Figure 8 of ACOE's 
IHA application), very little peer-reviewed research exists on the 
effects that confined blasting can have on marine animals near the 
blast (Keevin et al., 1999). The visual evidence from a typical 
confined blast is shown in Figure 9 of ACOE's IHA application.
    In confined blasting, the detonation is conveyed from the drill 
barge to the primer and the charge itself by Primacord and Detaline. 
These are used to safely fire the blast from a distance to ensure human 
safety from the blast. The Primacord and Detaline used on this project 
have a specific grain weight, and they burn like a fuse. They are not 
electronic. The time delay from activation to detonation of the charge 
is less than one second.

[[Page 6549]]

    To estimate the maximum poundage of explosives that may be utilized 
for this project, the ACOE has reviewed previous confined blasting 
projects, including San Juan Harbor, Puerto Rico in 2000, and Miami 
Harbor, Florida in 2005. Additional data was also reviewed from the New 
York Harbor deepening project (ACOE, 2004 and Keevin et al., 2005) and 
the Wilmington Harbor project (Settle et al., 2002). The San Juan 
Harbor and 2005 Miami Harbor projects are most similar to the existing 
project in general environment, hardness/massiveness of rock, and 
species composition. The San Juan Harbor project's heaviest confined 
blast event using explosives was 375 lbs (170.1 kg) per delay and in 
Miami it was 376 lbs (170.6 kg) per delay. Based on discussion with the 
ACOE's geotechnical engineers, it is expected that the maximum weight 
of delays for Miami Harbor would be larger since the rock is deeper, 
and expected to be harder and massive, in comparison to the previous 
two blasting projects.
    Based upon industry standards and ACOE Safety & Health Regulations, 
the confined blasting program would follow these operating guidelines:
     The weight of explosives to be used in each confined blast 
would be limited to the lowest poundage of explosives that can 
adequately break the rock.
     Drill patterns (i.e., holes in the array) are restricted 
to a minimum of 8 ft (2.4 m) separation from a loaded hole.
     Hours of confined blasting are restricted from two hours 
after sunrise to one hour before sunset to allow for adequate 
observation of the project area for marine mammals.
     Selection of explosive products and their practical 
application method must address vibration and air blast (overpressure) 
control for protection of existing structures and marine wildlife.
     Loaded blast holes would be individually delayed to reduce 
the maximum lbs per delay at point detonation, which in turn would 
reduce the mortality radius.
     The blast design would consider matching the energy in the 
``work effort'' of the borehole to the rock mass or target for 
minimizing excess energy vented into the water column or hydraulic 
shock.
     Delay timing adjustments with a minimum of 8 milliseconds 
(ms) between delay detonations to stagger the blast pressures and 
prevent cumulative addition of pressures in the water.

Test Blast Program

    Prior to implementing a construction blasting program, a test blast 
program would be completed. The test blast program would have all the 
same protective monitoring and mitigation measures in place for 
protected species as blasting operations for construction purposes. The 
purpose of the test blast program is to demonstrate and/or confirm the 
following:
     Drill boat capabilities and production rates;
     Ideal drill pattern for typical boreholes;
     Acceptable rock breakage for excavation;
     Tolerable vibration level emitted;
     Directional vibration; and
     Calibration of the environment.
    The test blast program begins with a single range of individually 
delayed holes and progresses up to the maximum production blast 
intended for use. The test blast program would take place in the 
project area and would count toward the pre-treatment of material, 
since the blasts of the test blast program would be cracking rock. Each 
test blast is designed to establish limits of vibration and air blast 
overpressure, with acceptable rock breakage for excavation. The final 
test event simulates the maximum explosive detonation as to size, 
overlying water depth, charge configuration, charge separation, 
initiation methods, and loading conditions anticipated for the typical 
production blast.
    The results of the test blast program would be formatted in a 
regression analysis with other pertinent information and conclusions 
reached. This would be the basis for developing a completely engineered 
procedure for the construction blasting plan.
    During the test blast program, the following data would be used to 
develop a regression analysis:
     Distance;
     Pounds per delay;
     Peak particles velocities (Threshold Limit Value [TVL]);
     Frequencies (TVL);
     Peak vector sum; and
     Air blast, overpressure.
    As part of the development of the protected species monitoring and 
mitigation protocols, which would be incorporated into the plans and 
specification for the project, ACOE would continue to coordinate with 
the resource agencies and non-governmental organizations (NGOs) to 
address concerns and potential impacts associated with the use of 
blasting as a construction technique.
    Additional details regarding the proposed confined blasting and 
dredging project can be found in the ACOE's IHA application and EIS. 
The EIS can also be found online at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.

Description of the Proposed Dates, Duration, and Specified Geographic 
Region

    At this time the ACOE has not been provided a blasting plan; 
however, the contractor has identified a more specific timeframe for 
the blasting to occur within the Port of Miami. Because Options A and B 
have not been exercised, the blasting in these areas have not been 
scheduled. As soon as the options are exercised and confined blasting 
scheduled, ACOE would notify NMFS. The current IHA expires on March 14, 
2014. The ACOE's contractor would have begun confined blasting the week 
prior to this expiration and to ensure no loss of time or slip in the 
schedule, the ACOE requests the new IHA be issued prior to the 
expiration of the existing IHA. The ACOE requested that the first IHA 
be issued by the end of July 2012, with an effective date of March 15, 
2013, to allow for the advertisement of the contract for construction 
in 2012; award the contract and provide the NTP to be selected in 2013 
to the selected contractor, resulting in construction work beginning in 
March 2014. The proposed construction activities are expected to last 
about to 24 months and at this time, it is possible that confined 
blasting could take place at any time during construction. The ACOE 
also notes that multiple IHAs (up to three, at least one additional IHA 
after 2014 to 2015) would be needed and requested for this project due 
to the project duration.
    The proposed confined blasting activities would be limited to 
waters shallower than 60 ft (18.3 m) and located entirely on the 
continental shelf and would not take place seaward of the outer reef. 
The specified geographic area of the construction would be within the 
boundaries of the Port of Miami, in Miami, Florida (see Figure 11 of 
the ACOE's IHA application). The Port of Miami is an island facility 
consisting of 518 upland acres and is located in the northern portion 
of Biscayne Bay in South Florida. The City of Miami is located on the 
west side of the Biscayne Bay; the City of Miami Beach is located on an 
island on the northeast side of Biscayne Bay, opposite of Miami. Both 
cities are located in Miami-Dade County, Florida, and are connected by 
several causeways crossing the bay. The Port of Miami is the 
southernmost major port on the Atlantic Coast. The Port of Miami's 
landside facilities are located on Dodge-Lummus Island, which has a GPS 
location 25[deg]46'05'' North 80[deg]09'40'' West. See Figure 11 of the 
ACOE's IHA application for more information on the

[[Page 6550]]

location of the project area in the Port of Miami.

Description of Marine Mammals in the Area of the Proposed Specified 
Activity

    Several cetacean species and a single species of sirenian are known 
to or could occur in the Miami Harbor action area and off the Southeast 
Atlantic coastline (see Table 1 below). Species listed as endangered 
under the U.S. Endangered Species Act (ESA), includes the humpback 
(Megaptera novaeangliae), sei (Balaenoptera borealis), fin 
(Balaenoptera physalus), blue (Balaenoptera musculus), North Atlantic 
right (Eubalaena glacialis), and sperm (Physeter macrocephalus) whale, 
and West Indian (Florida) manatee (Trichechus manatus latirostris). The 
marine mammals that occur in the Atlantic Ocean off the U.S. southeast 
coast belong to three taxonomic groups: mysticetes (baleen whales), 
odontocetes (toothed whales), and sirenians (the manatee). The West 
Indian manatee in Florida and U.S. waters is managed under the 
jurisdiction of the USFWS and therefore is not considered further in 
this analysis.
    Table 1 below outlines the marine mammal species and their habitat 
in the region of the proposed project area.

   Table 1--The Habitat and Conservation Status of Marine Mammals Inhabiting the Proposed Project Area in the
                                   Atlantic Ocean off the U.S. Southeast Coast
----------------------------------------------------------------------------------------------------------------
               Species                         Habitat                  ESA \1\                  MMPA \2\
----------------------------------------------------------------------------------------------------------------
                                                   Mysticetes
----------------------------------------------------------------------------------------------------------------
North Atlantic right whale (Eubalaena  Coastal and shelf......  EN.....................  D.
 glacialis).
Humpback whale (Megaptera              Pelagic, nearshore       EN.....................  D.
 novaeangliae).                         waters, and banks.
Bryde's whale (Balaenoptera brydei)..  Pelagic and coastal....  NL.....................  NC.
Minke whale (Balaenoptera              Shelf, coastal, and      NL.....................  NC.
 acutorostrata).                        pelagic.
Blue whale (Balaenoptera musculus)...  Pelagic and coastal....  EN.....................  D.
Sei whale (Balaenoptera borealis)....  Primarily offshore,      EN.....................  D.
                                        pelagic.
Fin whale (Balaenoptera physalus)....  Slope, mostly pelagic..  EN.....................  D.
----------------------------------------------------------------------------------------------------------------
                                                   Odontocetes
----------------------------------------------------------------------------------------------------------------
Sperm whale (Physeter macrocephalus).  Pelagic, deep seas.....  EN.....................  D.
Cuvier's beaked whale (Ziphius         Pelagic................  NL.....................  NC.
 cavirostris).
Gervais' beaked whale (Mesoplodon      Pelagic................  NL.....................  NC.
 europaeus).
True's beaked whale (Mesoplodon        Pelagic................  NL.....................  NC.
 mirus).
Blainville's beaked whale (Mesoplodon  Pelagic................  NL.....................  NC.
 densirostris).
Dwarf sperm whale (Kogia sima).......  Offshore, pelagic......  NL.....................  NC.
Pygmy sperm whale (Kogia breviceps)..  Offshore, pelagic......  NL.....................  NC.
Killer whale (Orcinus orca)..........  Widely distributed.....  NL NL EN (Southern       NC NC D (Southern
                                                                 Resident).               Resident, AT1
                                                                                          Transient).
Short-finned pilot whale               Inshore and offshore...  NL.....................  NC.
 (Globicephala macrorhynchus).
False killer whale (Pseudorca          Pelagic................  NL.....................  NC.
 crassidens).
Mellon-headed whale (Peponocephala     Pelagic................  NL.....................  NC.
 electra).
Pygmy killer whale (Feresa attenuata)  Pelagic................  NL.....................  NC.
Risso's dolphin (Grampus griseus)....  Pelagic, shelf.........  NL.....................  NC.
Bottlenose dolphin (Tursiops           Offshore, Inshore,       NL.....................  NC S (Biscayne Bay and
 truncatus).                            coastal, and estuaries.                           Central Florida
                                                                                          Coastal stocks) D
                                                                                          (Western North
                                                                                          Atlantic Coastal).
Rough-toothed dolphins (Steno          Pelagic................  NL.....................  NC.
 bredanensis).
Fraser's dolphin (Lagenodelphis        Pelagic................  NL.....................  NC.
 hosei).
Striped dolphin (Stenella              Pelagic................  NL.....................  NC.
 coeruleoalba).
Pantropical spotted dolphin (Stenella  Pelagic................  NL.....................  NC D (Northeastern
 attenuata).                                                                              Offshore).
Atlantic spotted dolphin (Stenella     Coastal to pelagic.....  NL.....................  NC.
 frontalis).
Spinner dolphin (Stenella              Mostly pelagic.........  NL.....................  NC D (Eastern).
 longirostris).
Clymene dolphin (Stenella clymene)...  Pelagic................  NL.....................  NC.
----------------------------------------------------------------------------------------------------------------
                                                    Sirenians
----------------------------------------------------------------------------------------------------------------
West Indian (Florida) manatee          Coastal, rivers, and     EN.....................  D.
 (Trichechus manatus latirostris).      estuaries.
----------------------------------------------------------------------------------------------------------------
\1\ U.S. Endangered Species Act: EN = Endangered, T = Threatened, NL = Not listed.
\2\ U.S. Marine Mammal Protection Act: D = Depleted, S = Strategic, NC = Not classified.

    The one species of marine mammal under NMFS jurisdiction known to 
commonly occur in close proximity to the blasting area of the Port of 
Miami is the Atlantic bottlenose dolphin, specifically the stocks 
living near the Port of Miami within Biscayne Bay (the Biscayne Bay 
stock) or transiting the outer entrance channel (Western North Atlantic 
Central Florida Coastal stock).

Atlantic Bottlenose Dolphin

    Atlantic bottlenose dolphins are distributed worldwide in tropical 
and temperate waters, and in U.S. waters occur in multiple complex 
stocks along

[[Page 6551]]

the U.S. Atlantic coast. The coastal morphotype of bottlenose dolphins 
is continuously distributed along the Atlantic coast south of Long 
Island, New York, to the Florida peninsula, including inshore waters of 
the bays, sounds, and estuaries. Except for animals residing within the 
Southern North Carolina and Northern North Carolina Estuarine Systems 
(e.g., Waring et al., 2009), estuarine dolphins along the U.S. east 
coast have not been previously included in stock assessment reports. 
Several lines of evidence support a distinction between dolphins 
inhabiting coastal waters near the shore and those present in the 
inshore waters of the bays, sounds, and estuaries. Photo-ID and genetic 
studies support the existence of resident estuarine animals in several 
inshore areas of the southeastern United States (Caldwell, 2001; 
Gubbins, 2002; Zolman, 2002; Mazzoil et al., 2005; Litz, 2007), and 
similar patterns have been observed in bays and estuaries along the 
Gulf of Mexico coast (Well et al., 1987; Balmer et al., 2008). Recent 
genetic analyses using both mitochondrial DNA and nuclear 
microsatellite markers found significant differentiation between 
animals biopsied along the coast and those biopsied within the 
estuarine systems at the same latitude (NMFS, unpublished data). 
Similar results have been found off the west coast of Florida (Sellas 
et al., 2005).

Biscayne Bay Stock

    Biscayne Bay is a shallow estuarine system located along the 
southeast coast of Florida in Miami-Dade County. The Bay is generally 
shallow (depths less than 5 m [16.4 ft]) and includes a diverse range 
of benthic communities including seagrass beds, soft coral and sponge 
communities, and mud flats. The northern portion of Biscayne Bay is 
surrounded by the cities of Miami and Miami Beach and is therefore 
heavily influenced by industrial and municipal pollution sources. The 
water flow in this portion of Biscayne Bay is very restricted due to 
the construction of dredged islands (Bialczak et al., 2001). In 
contrast, the central and southern portions of Biscayne Bay are less 
influenced by development and are better flushed. Water exchange with 
the Atlantic Ocean occurs through a broad area of grass flats and tidal 
channels termed the Safety Valve. Biscayne Bay extends south through 
Card Sound and Barnes Sound, and connects through smaller inlets to 
Florida Bay.
    The Biscayne Bay stock of bottlenose dolphins is bounded by 
Haulover Inlet to the north and Card Sound Bridge to the south. This 
range corresponds to the extent of confirmed home ranges of bottlenose 
dolphins observed residing in Biscayne Bay by a long-term photo-ID 
study conducted by the Southeast Fisheries Science Center (Litz, 2007; 
SEFSC unpublished data). It is likely that the range of Biscayne Bay 
dolphins extends past these boundaries; however, there have been few 
surveys outside of this range. These boundaries are subject to change 
upon further study of dolphin home ranges within the Biscayne Bay 
estuarine system and comparison to an extant photo-ID catalog from 
Florida Bay to the south.
    Dolphins residing within estuaries north of this stock along the 
southeastern coast of Florida are currently not included in a stock 
assessment report. There are insufficient data to determine whether 
animals in this region exhibit affiliation to the Biscayne Bay stock, 
the estuarine stock further to the north in the Indian River Lagoon 
Estuarine System (IRLES), or are simply transient animals associated 
with coastal stocks. There is relatively limited estuarine habitat 
along this coastline; however, the Intracoastal Waterway extends north 
along the coast to the IRLES. It should be noted that during 2003 to 
2007, there were three stranded bottlenose dolphins in this region in 
enclosed waters. One of these had signs of human interaction from a 
boat strike and another was identified as an offshore morphotype of 
bottlenose dolphin.
    Bottlenose dolphins have been documented in Biscayne Bay since the 
1950's (Moore, 1953). Live capture fisheries for bottlenose dolphins 
are known to have occurred throughout the southeastern U.S. and within 
Biscayne Bay during the 1950's and 1960's; however, it is unknown how 
many individuals may have been removed from the population during this 
period (Odell, 1979; Wells and Scott, 1999).
    The Biscayne Bay bottlenose dolphin stock has been the subject of 
an ongoing photo-ID study conducted by the NMFS SEFSC since 1990. From 
1990 to 1991, preliminary information was collected focusing on the 
central portion of Biscayne Bay. The survey was re-initiated in 1994, 
and it was expanded to include the northern portion of Biscayne Bay and 
south to the Card Sound Bridge in 1995 (SEFSC unpublished data; Litz, 
2007). Through 2007, the photo-ID catalog included 229 unique 
individuals. Approximately 80% of these individuals may be long-term 
residents with multiple sightings over the 17 years of the study 
(SEFSC, unpublished data). Analyses of the sighting histories and 
associations of individuals from the Biscayne Bay segregated along a 
north/south gradient (Litz, 2007).
    Remote biopsy samples of Biscayne Bay animals were collected 
between 2002 and 2004 for analyses of population genetic structure and 
persistent organic pollutant concentrations in blubber. Genetic 
structure was investigated using both mitochondrial DNA and nuclear 
(microsatellite) markers, and the data from Biscayne Bay were compared 
to data from Florida Bay dolphins to the south (Litz, 2007). Within 
Biscayne Bay, dolphins sighted primarily in the northern half of 
Biscayne Bay were significantly differentiated from those sighted 
primarily in the southern half at the microsatellite loci but not at 
the mitochondrial locus. There was not sufficient genetic information 
between these groups to indicate true population subdivision (Litz, 
2007). However, genetic differentiation was found between the Biscayne 
Bay and Florida Bay dolphins in both markers (Litz, 2007). The observed 
genetic differences between resident animals in Biscayne Bay and those 
in an adjacent estuary combined with the high levels of sight fidelity 
observed, demonstrate that the resident Biscayne Bay bottlenose 
dolphins are a demographically distinct population stock.
    The total number of bottlenose dolphins in the Biscayne Bay stock 
is unknown. During small boat surveys between 2003 and 2007, 157 unique 
individuals were identified using standard methods, however, this 
catalog size does not represent a valid estimate of population size 
because the residency patterns of dolphins in Biscayne Bay is not fully 
understood. Litz (2007) determined that 69 animals in Biscayne Bay have 
a northern home range. Based on Waring et al. (2010), the maximum 
population of animals that may be in the project area is equal to the 
total number of uniquely identified animals for the entire photo-ID 
study of Biscayne Bay--229 individuals. Present data are insufficient 
to calculate a minimum population estimate, and to determine the 
population trends, for the Biscayne Bay stock of bottlenose dolphins. 
The total human-caused mortality and serious injury for this stock is 
unknown and there is insufficient information available to determine 
whether the total fishery-related mortality and serious injury for this 
stock is insignificant and approaching zero mortality and serious 
injury rate. Documented human-caused mortalities in recreational 
fishing gear entanglement and ingestion of gear reinforce concern for 
this stock. Because the stock size is currently unknown, but likely 
small and relatively few

[[Page 6552]]

mortalities and serious injuries would exceed potential biological 
removal, NMFS considers this stock to be a strategic stock.

Western North Atlantic Central Florida Coastal Stock

    On the Atlantic coast, Scott et al. (1988) hypothesized a single 
coastal migratory stock ranging seasonally from as far north as Long 
Island, to as far south as central Florida, citing stranding patterns 
during a high mortality event in 1987 to 1988 and observed density 
patterns. More recent studies demonstrate that the single coastal 
migratory stock hypothesis is incorrect, and there is instead a complex 
mosaic of stocks (McLellan et al., 2003; Rosel et al., 2009).
    The coastal morphotype is morphologically and genetically distinct 
from the larger, more robust morphotype primarily occupying habitats 
further offshore (Hoelzel et al., 1998; Mead and Potter, 1995; Rosel et 
al., 2009). Aerial surveys conducted between 1978 and 1982 (CETAP, 
1982) north of Cape Hatteras, North Carolina, identified two 
concentrations of bottlenose dolphins, one inshore of the 82 ft (25 m) 
isobath and the other offshore of the 164 ft (50 m) isobath. The lowest 
density of bottlenose dolphins was observed over the continental shelf, 
with higher densities along the coast and near the continental shelf 
edge. It was suggested, therefore, that north of Cape Hatteras, North 
Carolina, the coastal morphotype is restricted to waters less than 82 
ft deep (Kenney, 1990). Similar patterns were observed during summer 
months in more recent aerial surveys (Garrison and Yeung, 2001; 
Garrison et al., 2003). However, south of Cape Hatteras during both 
winter and summer months, there was no clear longitudinal discontinuity 
in bottlenose dolphin sightings (Garrison and Yeung 2001; Garrison et 
al., 2003). To address the question of distribution of coastal and 
offshore morphotypes in waters south of Cape Hatteras, tissue samples 
were collected from large vessel surveys during the summers of 1998 and 
1999, from systematic biopsy sampling efforts in nearshore waters from 
New Jersey to central Florida conducted in the summers of 2001 and 
2002, and from winter biopsy collection effort in 2002 and 2003 in 
nearshore continental shelf waters of North Carolina and Georgia. 
Additional biopsy samples were collected in deeper continental shelf 
waters south of Cape Hatteras during the winter of 2002. Genetic 
analyses using mitochondrial DNA sequences of these biopsies identified 
individual animals to the coastal or offshore morphotype. Using the 
genetic results from all surveys combined, a logistic regression was 
used to model the probability that a particular bottlenose dolphin 
group was of the coastal morphotype as a function of environmental 
variables including depth, sea surface temperature, and distance from 
shore. These models were used to partition the bottlenose dolphin 
groups observed during aerial surveys between the two morphotypes 
(Garrison et al., 2003).
    The genetic results and spatial patterns observed in aerial surveys 
indicate both regional and seasonal differences in the longitudinal 
distribution of the two morphotypes in coastal Atlantic waters. 
Generally, from biopsy samples collected, the coastal morphotype is 
found in nearshore waters, the offshore morphotype in deeper waters and 
a spatial overlap between the two morphotypes in intermediate waters. 
More information on the seasonal differences and genetic studies off of 
the Carolina's, Georgia, and Florida, differentiating morphotypes of 
bottlenose dolphins can be found online in the NMFS stock assessment 
reports.
    In summary, the primary habitat of the coastal morphotype of 
bottlenose dolphin extends from Florida to New Jersey during summer 
months and in waters less than 65.6 ft (20 m) deep, including estuarine 
and inshore waters.
    In addition to inhabiting coastal nearshore waters, the coastal 
morphotype of bottlenose dolphin also inhabits inshore estuarine waters 
along the U.S. east coast and Gulf of Mexico (Wells et al., 1987; Wells 
et al., 1996; Scott et al., 1990; Weller, 1998; Zolman, 2002; Speakman 
et al., 2006; Stolen et al., 2007; Balmer et al., 2008; Mazzoil et al., 
2008). There are multiple lines of evidence supporting demographic 
separation between bottlenose dolphins residing within estuaries along 
the Atlantic coast. In Biscayne Bay, Florida, there is a similar 
community of bottlenose dolphins with evidence of year-round residents 
that are genetically distinct from animals residing in a nearby estuary 
in Florida Bay (Litz, 2007). A few published studies demonstrate that 
there are significant genetic distinctions and differences between 
animals in nearshore coastal waters and estuarine waters (Caldwell, 
2001; Rosel et al., 2009). Despite evidence for genetic differentiation 
between estuarine and nearshore populations, the degree of spatial 
overlap between these populations remains unclear. Photo-ID studies 
within estuaries demonstrate seasonal immigration and emigration and 
the presence of transient animals (e.g., Speakman et al., 2006). In 
addition, the degree of movement of resident estuarine animals into 
coastal waters on seasonal or shorter time scales is poorly understood. 
However, for the purposes of this analysis, bottlenose dolphins 
inhabiting primarily estuarine habitats are considered distinct from 
those inhabiting coastal habitats. Initially, a single stock of coastal 
morphotype bottlenose dolphins was thought to migrate seasonally 
between New Jersey (summer months) and central Florida based on 
seasonal patterns in strandings during a large scale mortality event 
occurring during 1987 to 1988 (Scott et al., 1988). However, re-
analysis of stranding data (McLellan et al., 2003) and extensive 
analysis of genetic (Rosel et al., 2009), photo-ID (Zolman, 2002) and 
satellite telemetry (NMFS, unpublished data) data demonstrate a complex 
mosaic of coastal bottlenose dolphin stocks. Integrated analysis of 
these multiple lines of evidence suggests that there are five coastal 
stocks of bottlenose dolphins: The Northern Migratory and Southern 
Migratory stocks, a South Carolina/Georgia Coastal stock, a Northern 
Florida Coastal stock, and a Central Florida Coastal stock.
    The spatial extent of these stocks, their potential seasonal 
movements, and their relationships with estuarine stocks are poorly 
understood. More information on the migratory movements and genetic 
analyses of bottlenose dolphins can be found online in the NMFS stock 
assessment reports.
    The NMFS stock assessment report addresses the Central Florida 
Coastal stock, which is present in coastal Atlantic waters from 
29.4[deg] North south to the western end of Vaca Key (approximately 
24.69[deg] North to 81.11[deg] West) where the stock boundary for the 
Florida Keys stock begins (see Figure 1 of the NMFS Stock Assessment 
Report). There has been little study of bottlenose dolphin stock 
structure in coastal waters of southern Florida; therefore the southern 
boundary of the Central Florida stock is uncertain. There is no obvious 
boundary defining the offshore extent of this stock. The combined 
genetic and logistic regression analysis (Garrison et al., 2003) 
indicated that in waters less than 32.8 ft (10 m) depth, 70% of the 
bottlenose dolphins were of the coastal morphotype. Between 32.8 ft and 
65.6 ft depth, the percentage of animals of the coastal morphotype 
dropped precipitously, and at depths greater than 131.2 ft (40 m) 
nearly all (greater than 90%) animals were of the offshore morphotype. 
These spatial patterns may not apply in the Central Florida Coastal 
stock, as there is a

[[Page 6553]]

significant change in the bathymetric slope and a close approach of the 
Gulf Stream to the shoreline south of Cape Canaveral.
    Aerial surveys to estimate the abundance of coastal bottlenose 
dolphins in the Atlantic were conducted during winter (January to 
February) and summer (July to August) of 2002. Abundance estimates for 
bottlenose dolphins in each stock were calculated using line-transect 
methods and distance analysis (Buckland et al., 2001). More information 
on the survey tracklines, design, effort, animals sighted, and methods 
for calculating estimated abundance can be found online in the NMFS 
stock assessment reports.
    The estimated best and minimum population for the Central Florida 
Coastal Stock is 6,318 and 5,094 animals, respectively. There are 
insufficient data to determine the population trends for this stock. 
From 1995 to 2001, NMFS recognized only a single migratory stock of 
coastal bottlenose dolphins in the western North Atlantic, and the 
entire stock was listed as depleted. This stock structure was revised 
in 2002 to recognize both multiple stocks and seasonal management units 
and again in 2008 and 2010 to recognize resident estuarine stocks and 
migratory and resident coastal stocks. The total U.S. fishery-related 
mortality and serious injury for the Central Florida Coastal stock 
likely is less than 10% of the calculated PBR, and thus can be 
considered to be insignificant and approaching zero mortality and 
serious injury rate. However, there are commercial fisheries 
overlapping with this stock that have no observer coverage. This stock 
retains the depleted designation as a result of its origins from the 
originally delineated depleted coastal migratory stock. The species is 
not listed as threatened or endangered under the ESA, but this is a 
strategic stock due to the depleted listing under the MMPA.
    Further information on the biology and local distribution of these 
species and others in the region can be found in ACOE's IHA 
application, which is available upon request (see ADDRESSES), and the 
NMFS Marine Mammal Stock Assessment Reports, which are available online 
at: https://www.nmfs.noaa.gov/pr/species/.

Potential Effects on Marine Mammals

    In general, potential impacts to marine mammals from explosive 
detonations could include mortality, serious injury, as well as Level A 
harassment (injury) and Level B harassment. In the absence of 
mitigation, marine mammals could be killed or injured as a result of an 
explosive detonation due to the response of air cavities in the body, 
such as the lungs and bubbles in the intestines. Effects would be 
likely to be most severe in near surface waters where the reflected 
shock wave creates a region of negative pressure called ``cavitation.''
    A second potential possible cause of mortality (in the absence of 
mitigation) is the onset of extensive lung hemorrhage. Extensive lung 
hemorrhage is considered debilitating and potentially fatal. 
Suffocation caused by lung hemorrhage is likely to be the major cause 
of marine mammal death from underwater shock waves. The estimated range 
for the onset of extensive lung hemorrhage to marine mammals varies 
depending upon the animal's weight, with the smallest mammals having 
the greatest potential hazard range.
    NMFS's criteria for determining potential for non-lethal injury 
(Level A harassment) from explosives are the peak pressure that would 
result in: (1) The onset of slight lung hemorrhage, or (2) a 50 percent 
probability level for a rupture of the tympanic membrane (TM). These 
are injuries from which animals would be expected to recover on their 
own.
    NMFS has established dual criteria for what constitutes Level B 
harassment: (1) An energy based temporary threshold shift (TTS) in 
hearing at received sound levels of 182 dB re 1 [mu]Pa\2\-s cumulative 
energy flux in any 1/3 octave band above 100 Hz for odontocetes 
(derived from experiments with bottlenose dolphins (Ridgway et al., 
1997; Schlundt et al., 2000); and (2) 12 psi peak pressure cited by 
Ketten (1995) as associated with a safe outer limit for minimal, 
recoverable auditory trauma (i.e., TTS). The threshold for sub-TTS 
behavioral harassment is 177 dB re 1 [mu]Pa\2\ s. The Level B 
harassment zone is the distance from the mortality, serious injury, 
injury (Level A harassment) zone to the radius where neither of these 
criterion is exceeded.

     Table 2--NMFS's Threshold Criteria and Metrics Utilized for Impact Analyses From the Use of Explosives
----------------------------------------------------------------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
            Mortality             Level A Harassment (Non-lethal injury)  Level B Harassment  Level B Harassment
                                                                           (Non-injurious;     (Non-injurious
                                                                           TTS and             behavioral, Sub-
                                                                           associated          TTS)
                                                                           behavioral
                                                                           disruption [dual
                                                                           criteria])
----------------------------------------------------------------------------------------------------------------
31 psi-msec (onset of severe      205 dB re 1         13 psi-msec         182 dB re 1         177 dB re 1
 lung injury [mass of dolphin      [mu]Pa\2\[middot]   positive pressure   [mu]Pa\2\[middot]   [mu]Pa\2\[middot]
 calf]).                           s EFD (50 percent   (onset of slight    s EFD*; 23 psi      s EFD* (for
                                   of animals would    lung injury).       peak pressure (<    multiple
                                   experience TM                           2,000 lb) 12 psi    detonations
                                   rupture).                               peak pressure (>    only).
                                                                           2,000 lb).
----------------------------------------------------------------------------------------------------------------
* Note: In greatest \1/3\-octave band above 10 Hz or 100 Hz.

    The primary potential impact to the Atlantic bottlenose dolphins 
occurring in the Port of Miami action area from the proposed 
detonations is Level B harassment incidental to noise generated by 
explosives. In the absence of any monitoring or mitigation measures, 
there is a very small chance that a marine mammal could be injured, 
seriously injured, or killed when exposed to the energy generated from 
an explosive force on the sea floor. However, the ACOE and NMFS believe 
that the monitoring and mitigation measures would preclude this 
possibility in the case of this particular specified activity.
    Non-lethal injurious impacts (Level A harassment) are defined in 
this IHA as TM rupture and the onset of slight lung injury. The 
threshold for Level A harassment corresponds to a 50 percent rate of TM 
rupture, which can be stated in terms of an energy flux density (EFD) 
value of 205 dB re 1 [mu]Pa\2\ s. TM rupture is well-correlated with 
permanent hearing impairment (Ketten, 1998) indicates a 30 percent 
incidence of permanent threshold shift (PTS) at the same threshold. The 
farthest distance from the source at which an animal is exposed to the 
EFD level for the Level A harassment threshold is unknown at this time.
    Level B (non-injurious) harassment includes temporary (auditory) 
threshold

[[Page 6554]]

shift (TTS), a slight, recoverable loss of hearing sensitivity. One 
criterion used for TTS is 182 dB re 1 [mu]Pa\2\ s maximum EFD level in 
any 1/3-octave band above 100 Hz for toothed whales (e.g., dolphins). A 
second criterion, 23 psi, has been established by NMFS to provide a 
more conservative range of TTS when the explosive or animals approaches 
the sea surface, in which case explosive energy is reduced, but the 
peak pressure is not. For the project in Miami Harbor, the distance 
from the blast array at which the 23 psi threshold could be met for 
various charge detonation weights can be, and has been calculated.
    The threshold for sub-TTS behavioral harassment is 177 dB re 1 
[mu]Pa\2\ s. However, as described previously, this criterion would not 
apply to the ACOE's activity because there would only be a maximum of 
two blasting events a day (minimum four to six hours apart), and the 
multiple (staggered) detonations are within a few milliseconds of each 
other and do not last more than a few seconds in total duration per a 
blasting event.
    For a fully confined blast, the pressure at the edge of the danger 
zone is expected to be 6 psi. Utilizing the pressure data collected the 
Miami Harbor Phase II project in 2005, for a maximum charge weight of 
450 lbs in a fully confined blast, the pressure is expected to be 22 
psi approximately 700 ft (213.4 m) from the blast, which is below the 
threshold for Level B harassment (i.e., 23 psi criteria for explosives 
less than 2,000 lb). However to ensure the protection of marine 
mammals, and in case of an incident where a detonation is not fully 
confined, the ACOE assumes that any animal within the boundaries of a 
designated ``danger zone'' at the time of detonation would be taken by 
Level B harassment.
    The ACOE is planning to implement, and NMFS has required, a series 
of monitoring and mitigation measures to protect marine mammals from 
the potential impacts of the proposed confined blasting activities. The 
ACOE has designated a ``danger zone'' as the area within which the 
potential for Level B harassment occurs, and the ``exclusion zone'' as 
the area within which if an animal crosses and enters that zone then 
the confined blast would be delayed until the animal leaves the zone of 
its own volition. The exclusion zone i