Amendment 0003 Attachment USCG LALB IHA Request Revised Draft 20200424.pdf

Draft Request for Incidental Harassment Authorization for Offshore Patrol Cutter Homeporting at United States Coast Guard

Base Los Angeles/Long Beach, California

Prepared for:

United States Coast Guard Facilities Design & Construction Center

915 2nd Avenue Federal Building Room 2664 Seattle, WA 98174

Task: 70Z05018RLALBOP00

Report Date: April 2020

Prepared By:

2000 Center Street, Suite 303 Berkeley, CA 94704

(510) 835-2761 www.TranSystems.com

USCG Base LA/LB OPC Homeporting April 2020 IHA Request ii

Table of Contents Executive Summary

Section 1 Description of Activities

Introduction

Proposed Action

Section 2 Dates, Duration, and Location of Activity

Section 3 Affected Species Status and Distribution

Introduction

California Sea Lion

Pacific Harbor Seal

Bottlenose Dolphin

Short-beaked Common Dolphin

Gray Whale

Section 4 Type of Incidental Taking Authorization Requested

Take Authorization Request

Method of Take

Section 5 Take Estimates for Marine Mammals

Fundamentals of Sound

Applicable Noise Criteria

Estimation of Pile Driving Sound

5.3.1 Underwater Noise from Impact Pile Driving

5.3.1.1. Underwater Noise Modeling

5.3.1.2. Modeling Assumptions

5.3.1.3. Estimation of Pile Driving Noise

5.3.2 Airborne Noise

Description and Estimation of Take

5.4.1 California Sea Lion Take

5.4.2 Pacific Harbor Seal Take

5.4.3 Bottlenose Dolphin Take

5.4.4 Short-beaked Common Dolphin Take

5.4.5 Gray Whale Take

5.4.6 Summary

Section 6 Affected Status and Distribution of Species Potentially Affected

Effects of Underwater Noise on Marine Mammals iii

Expected Responses to Pile Driving

Effects of Airborne Noise on Marine Mammals

Effects of Human Disturbance on Marine Mammals

Section 7 Anticipated Impacts on Subsistence Uses

Anticipated Impacts on Subsistence Uses

Section 8 Anticipated Impacts on Habitat

Anticipated Impacts on Habitat

Section 9 Anticipated Habitat Impacts on Marine Mammals and Likelihood of Restoration

Anticipated Effects of Habitat on Marine Mammals

Section 10 Mitigation Measures

Description of Mitigation Measures

Mitigation Effectiveness

Section 11 Arctic Plan of Cooperation

Applicability of Arctic Plan of Cooperation

Section 12 Monitoring and Reporting Measures

Monitoring and Reporting Measures

Section 13 List of Preparers

Preparers

References

Tables Table 3-1 Stock Assessment of Marine Mammals Present in the Los Angeles/Long Beach Harbor Table 5-1: Marine Mammal Injury and Disturbance Thresholds Table 5-2: Summary of Potential Pile Driving Activity Table 5-3: Data Used to Estimate Underwater Sound from Pile Driving Table 5-4: Estimated Distances of Level A and B Noise Thresholds Table 5-5 Extent of Sound Pressure Levels for Airborne Noise Table 5-6 Summary of Potential Take for All Species Table 8-1: EFH Managed Species Potentially Occurring in the Project Area

Appendices Appendix A: Noise Data

Executive Summary United States Coast Guard Base Los Angeles/Long Beach is located on 27 acres of government‐owned land on the southern tip of Terminal Island within the Los Angeles Harbor. The Base runs along the western half of Reservation Point at the mouth of Los Angeles Main Channel, which provides principal access to the Port of Los Angeles. The proposed action includes construction of facilities to homeport two OPC at Base LA/LB including a new Maintenance and Weapons Division MWD facility, warehouse modifications, building 16 modifications, waterfront improvements, and associated site/utility work. The proposed action waterfront improvements includes a new 30-foot wide, approximately 265-feet long concrete pile supported wharf extension. The wharf extension will include fendering, mooring fixtures, power mounds, water and sanitary sewer shore ties that will provide utility connections for both bow north, and bow south OPC mooring.

In support of the proposed work, the United States Coast Guard is requesting Level B Take from the National Oceanic and Atmospheric Administration National Marine Fisheries Service for five species that may be present in the project vicinity. These species include the California sea lion, Pacific harbor seal, bottlenose dolphin, short-beaked common dolphin, and gray whale.

Section 1 Description of Activities

Introduction United States Coast Guard (USCG) Base Los Angeles/Long Beach (LA/LB) is located on 27 acres of government‐owned land on the southern tip of Terminal Island within the Los Angeles Harbor. The Base runs along the western half of Reservation Point at the mouth of Los Angeles Main Channel which provides principal access to the Port of Los Angeles (Figure 1). Base LA/LB is accessed from the mainland via Interstates 110 (Harbour Freeway), 710 (Long Beach Freeway), and the Terminal Island Freeway. Base LA/LB provides several personnel support services on‐site like warehouse and maintenance facilities and administration buildings.

Government housing is not available on Base. Base LA/LB is currently the homeport for a buoy tender, seven small boats, and four Fast Response Cutters (FRC). Base LA/LB has three piers along its western boundary (listed from north to south) (Figure 2):

1. Industrial wharf that berths the CGC GEORGE COBB buoy tender and supports the Aids to Navigation (ANT) mission.

2. Medium Endurance Cutters (WMEC) Pier that forms the western boundary of the small boat basin.

3. High Endurance Cutters (WHEC) Pier that is connected to and extends south from the WMEC Pier forming the WMEC/WHEC Pier. The WMEC/WHEC Pier is 1,255 feet long by 30 feet wide.

Figure 1: USCG Base LA/LB Location and Vicinity Map

The WMEC Pier was built in the 1950s and is approximately 227 feet long by 30 feet wide and supported by concrete piles with timber fender piles, wales, and chocks. The WHEC Pier was built in 1986 and is approximately 1,028 feet long by 30 feet wide and supported by concrete piles with foam‐filled fenders with timber‐bearing panels supported on steel H‐piles. The water depths at the moorings are 34 feet at the WMEC Pier and 36 feet to 39 feet at the WHEC Pier. Recent bathymetry from 2013 indicates the channel depth adjacent to the WMEC/WHEC Pier is approximately 57 feet (USCG 2016). Base LA/LB was previously the homeport of two 378‐foot WHECs —the CGC CHASE and CGC HAMILTON — including a total of 346 personnel. These two vessels were relocated to Naval Base San Diego in 1999. Since that time, Base LA/LB’s WHEC Pier has been primarily used by visiting long‐range cutters and has not functioned as a permanent homeport for any long‐ range cutters (USCG, 2016).

Five tenant commands have boats on trailers (or just trailers) stored at Base LA/LB: Port Security Unit (PSU) 311, maritime safety and security (MSST) 91103, Station LA/LB, and CGC GEORGE COBB. The PSU and MSST stores its boats/trailers on the concrete apron in front of their boat/engineering buildings (Buildings 50 and 51, respectively). The ANT stores its boats/trailers under a metal roof attached to Building 18. Station LA/LB stores its two boats/trailers near the boat haul-out finger pier. CGC GEORGE COBB stores its boats/trailers just south of Building 12 in the buoy yard. There is no excess capacity for boat/trailer storage at any of these locations. Tenants can remove small boats from the water using either the boat haul-out pier located just south of the Industrial Wharf or the 6‐ton jib crane in the small boat basin.

Proposed Action The proposed action includes construction of facilities to homeport two OPC at Base LA/LB including a new Maintenance and Weapons Division (MWD) facility, warehouse modifications, building 16 modifications, waterfront improvements, and associated site/utility work. The proposed action waterfront improvements includes a new 30-foot wide, approximately 265-feet long concrete pile supported wharf extension. The wharf extension will include fendering, mooring fixtures, power mounds, water and sanitary sewer shore ties that will provide utility connections for both bow north, and bow south OPC mooring. The proposed action includes removal of existing, and replacement with new, potable water, fire water, and sewer pipelines/systems from the respective shore side points of connection to the existing pier, and extending to the new OPC pier and berths.

The waterfront improvements include repair of the bank erosion area and placement of rock slope protection near the new electrical substation. The shore side proposed action includes the OPC MWD Support Facility comprised of approximately 10,550 SF new construction adjacent to and south of the FRC Maintenance Assistance Team (MAT) building, and approximately 1,050 SF of new storage space adjacent to and east of the existing FRC MAT building. It is intended that the OPC MWD Facility will support two OPCs. Crew and support personnel parking requirements for the OPCs will be accommodated by existing Base parking spaces, and will be augmented by refurbished and new parking spaces as shown on the plans. A minimum of 41 new parking spaces will be constructed, with an additional 105 parking spaces to be refurbished, for a total of 146 spaces to support two OPC’s. The proposed site for the new MWD Facility building shall be located immediately adjacent to and south of the FRC MAT building. The landside work includes removal and relocation of two ceremonial cannons. A general layout of the facility plan is provided in Figure 2.

Figure 2: Base LA/LB OPC Homeport Proposed Layout

Section 2 Dates, Duration, and Location of Activity The proposed pile driving is anticipated to occur during two in water work windows, the first between February 1st, 2021 and April 5th, 2021, and the second between September 1st, 2021, and February 1st, 2022. Dimension of pile to be used will be determined by the design build contractor. The estimated pile size will be between a minimum size of 16-inch square or octagonal pile and maximum size of 30-inch round pile. It is estimated that three to four vertical piles can be installed each working day, which would require up to 17 production days of pile driving activities for support of the new wharf extension. Once the new wharf deck is complete there will be follow-up pile driving work for the fender stations. An estimated 6 fender piles can be installed each day which equate to 18 production days to install the estimated 24-inch square concrete fender piling and 3 additional days to install the smaller corner protection piling. A total of 38 full production pile driving days are anticipated. There should be some accommodation for loss due to production delays or adverse weather which may result in a less than full production day. Pile driving would occur at the USCG Base LA/LB OPC Homeport Project wharf extension area, as located in Figure 2. The exact timeframe of pile instalation and pile size to be utilized will be confirmed after the award of the Design/Build contract.

Section 3 Affected Species Status and Distribution

Introduction There are five marine mammal species that may occur or move through the waters near or within the project area. These include the California sea lion, pacific harbor seal, bottlenose dolphin, short-beaked common dolphin, and gray whale. Gray whales may be rare in the project area and vicinity. These marine mammals are managed under the jurisdiction of the National Marine Fisheries Service (NMFS), a division of the National Oceanic and Atmospheric Administration (NOAA). Table 3-1 describes the stock numbers, likelihood of occurrence, and season of occurrence for these species in the project vicinity.

Table 3-1 Stock Assessment of Marine Mammals Present in the Los Angeles/Long Beach Harbor

Species Stock Name Stock Abundance Relative Occurrence in Long

Beach and Los Angeles Harbors

Season(s) of Occurrence

California sea lion Zalophus californianus U.S. Stock 257,606 Common Year round

Pacific harbor seal Phoca vitulina California Stock 30,968 Common Year round

Bottlenose dolphin Tursips truncatus

California Coastal Stock 453 Occasional Year round

Short-beaked Common Dolphin Delphinus delphis

California/Oregon /Washington Stock 969,861 Occasional Year round

Gray Whale Eschrichtius robustus

Eastern North Pacific Stock 26,960 Rare Year round

Source: NOAA 2015, 2017a, 2017b, 2019a, 2019e

California Sea Lion The California sea lion (Zalophus californianus) is a part of the Otariidae family, differentiated from other pinniped families by the presence of external ear flaps. California sea lions are sexually dimorphic. Males typically approach lengths up to eight feet and may weigh up to 800 pounds, while females are typically around six feet in length and range from 200 to 240 pounds. The average lifespan is 20 to 30 years, with sexual maturity being reached between four and five years. Pups are dark brown at birth, becoming blonde to tan in color as they approach maturity. Adult males tend to have darker coloration than juveniles and females. California sea lions are social animals that participate in group hunting and may cooperate with other species, such as dolphins, when hunting large schools of fish. They have been observed in groups of several hundred individuals or more.

While they are social on land and water, males will aggressively defend their territory during breeding season and females will fight with other females to defend their pups. Their diet consists of aquatic prey found in upwelling areas, including squid, anchovies, mackerel, rockfish, and sardines. They are opportunistic feeders that may take fish from commercial fishing gear, sport fishing lines, and fish passage facilities at dams and rivers.

While California sea lions can stay at sea for up to two weeks at a time, they often use haul-outs: out of water locations where they can rest, socialize, breed, and molt. Haul-out locations can include sandy beaches, rocky coves, marina docks, jetties, and buoys (NOAA 2019b).

California sea lions in the U.S. are not listed as threatened or endangered under the Endangered Species Act (ESA) or as depleted under the Marine Mammal Protection Act (MMPA). California sea lion stock is estimated to be at approximately 40% over its maximum net productivity level. It is therefore considered to be within its range of optimum sustainable population level (NOAA 2019b).

California sea lions were the most commonly observed marine mammal during biological surveys of the Los Angeles Harbor and Long Beach vicinity during the 2008 and 2013 to 2014 monitoring periods. Individuals were observed hauled-out and resting on buoys, docks, riprap shorelines, as well as docked cargo ships. They were frequently documented to be foraging near bait barges and fish markets, as well as in the wakes of fishing boats entering the Port Complex (MBC 2016).

Pacific Harbor Seal The Pacific harbor seal (Phoca vitulina var. richardsi) is a true seal, and is one of three subspecies of harbor seal. Five subspecies were recognized until recent genetic analysis failed to substantially differentiate between populations. True seals have no external ear flaps and are also known as crawling seals due to their flopping locomotion on land necessitated by their short flippers. Males and females are similar in size, with males being slightly larger. They reach six feet in length and can approach 300 pounds. Harbor seals may forage off shore, but are typically found in coastal waters. The Pacific harbor seal tends towards solitary activity while in the water, but will come ashore in groups at haul-outs. Haul-outs, generally consisting of rocks, reefs, or beach area, are used for rest, thermoregulation, social interaction, birthing and nursing pups, and predator avoidance. Typical prey species include fish, shellfish, and crustaceans, which are foraged for during shallow and deep dive hunting excursions. Mating occurs at sea, with pups being birthed during the spring and summer seasons. Pups are ready to swim and dive within minutes of birth. The nursing period lasts for four to six weeks (NOAA 2019f).

Pacific Harbor seals are found along the West Coast of North America from California, north to the Bering Sea.

They are a non-migratory species that ranges within 15 to 31 miles from home, but have been known to travel up to 249 miles from tagging locations.

The Pacific harbor seal is not listed as threatened or endangered under the ESA and is not designated as depleted under the MMPA in the California area. Human influenced mortalities fall below the calculated potential biological removal level (PBR), and they are therefore not considered to be a strategic stock under the MMPA

(NOAA 2015).

In the Los Angeles and Long Beach Harbors, Pacific harbor seals were much less common than California sea lions, accounting for approximately 26 percent of marine mammal observations. Harbor seals were more commonly observed in the outer harbor areas, resting or foraging along riprap shorelines, particularly in the vicinity of the outer harbor breakwaters (SAIC 2010, MBC 2016).

Bottlenose Dolphin The bottlenose dolphin (Tursiops truncates) is a member of the Delphinidae family, which encompasses species commonly recognized as dolphins. Bottlenose dolphins are named for their short, thick snout (rostrum). They are gray in color, ranging from almost white to almost black. Their bellies tend towards lighter colors, with the dorsal side being darker in color. Individuals living in nearshore coastal waters tend to be smaller and lighter in color than those that live offshore. Bottlenose dolphins range in length, from six to 13 feet, and can weigh between 300 and 1,400 pounds. Sexual maturity is reached between five to 13 years for females and between nine and 14 years in males. Females are pregnant for approximately 12 months. Once a calf is born, it is nursed for up to 20 months, and may stay with its mother from three to six years. Calves maintain a “baby position” while swimming, with the mother surfacing first, followed closely by the calf (NOAA 2019c). Bottlenose dolphin’s life expectancy exceeds 40 years, with females outliving males at 60 or more years in age. California bottlenose dolphins typically are found within 0.6 miles of shore (NOAA 2016). Bottlenose dolphins feed on a variety of prey, including fish, squid, and crustaceans. They forage for food either individually or cooperatively. Cooperative feeding may involve herding fish into a group, whereupon they take turns to charge through the group and feed.

Another technique involves trapping schools of fish against sand bars and seawalls.

The California coastal stock of bottlenose dolphin is not listed as threatened or endangered under the ESA and is not listed as depleted under the MMPA. They are not listed as a strategic stock under the MMPA due to a human influenced mortality rate that falls below the PBR (NOAA 2017a).

Bottlenose Dolphin individuals accounted for approximately two percent of all marine mammal observations during the most recent biological baseline survey of the Los Angeles and Long Beach harbors. The majority of observations involved individuals foraging in the outer harbor area (SEIC 2010, MBC 2016).

Short-beaked Common Dolphin Like the bottlenose dolphin, the short-beaked common dolphin (Delphinus delphis) is a member of the Delphinidae family, which encompasses species commonly recognized as dolphins. They are the most abundant cetacean off the California coast, and are found up to approximately 350 miles from the coastline (NOAA 2017).

Short-beaked common dolphins are closely related to and similar in form to long-beaked common dolphins.

Although they were once thought to be a single species, they differ slightly in size, appearance, and habitat preferences. The short-beaked common dolphin is less than six feet long, weighing approximately 170 pounds, with males being slightly larger than females. They have a rounded forehead (melon), a moderately long snout (rostrum), and a relatively long, triangular mid-back dorsal fin (NOAA 2019g). They have a distinctive hourglass color pattern, defined by a gray cape extending from the back of the head to below the dorsal fin, where a “V” is visible on either side of the body. A narrow dark stripe extends from the lower jaw to the flipper. The colors of juveniles are somewhat muted, becoming more apparent in adulthood. Males reach sexual maturity as early as five years of age and as late as 12 years. Calving takes place off the California coast during the winter, after a 10 to one month gestation period. Calves start to wean after approximately one year, and will remain dependent for another year or more. Short-beaked common dolphins can dive to depths of approximately 1,000 feet, but are typically active for feeding to approximately 100 feet. They typically feed on schooling fish and cephalopods migrating towards the surface at night. They will generally live to around 35 years in age.

Short-beaked common dolphins are not listed as threatened or endangered under the ESA, and are not listed as depleted under the MMPA. They are not listed as a strategic stock under the MMPA due to a human influenced mortality rate that falls below the PBR (NOAA 2017b).

Short-beaked common dolphins are not frequently observed in the Los Angeles and Long Beach harbor area, but are occasionally present. Observations during biological surveys in 2013 through 2014 included one observation of a pod of 40 individuals in the Los Angeles Main Channel. No other observations of short-beaked common dolphins were made during this survey period (MBC 2016).

Gray Whale Gray whales (Eschrichtius robustus) are large baleen whales comprising the only species in the Eschrichtiidae family. They range from 42 to 49 feet in length, and can weigh as much as 90,000 pounds. Females are slightly larger than males. They are the most frequently seen whale off the California coastline. They are recognizable by their lack of a dorsal fin and mottled gray color. They possess a dorsal hump with a series of six to 12 bumps known as knuckles. Adults carry a heavy load of barnacles, adding to the mottled coloring. Their tail flukes are close to 10 feet wide, with S-shaped trailing edges and a deep median notch. Gray whales are sexually mature between six and 12 years of age. Females will carry a single calf for 12 to 13 months. A newborn calf is approximately 14 to 16 feet long, and weights around 2,000 pounds. The average lifespan of Gray whales is unknown. One individual was estimated to be 75 to 80 years old at the time of death. Gray whales will travel either alone or in small groups, but may congregate in larger numbers at feeding and breeding grounds. They are bottom feeders that consume benthic and epibenthic invertebrates, such as amphipods. Feeding is accomplished by rolling on their sides while swimming along the bottom, filtering pretty out of the bottom sediments through 130 to 180 course baleen plates on each side of their upper jaws. Feeding areas can be identified by long trails left in the bottom sediment knows as “feeding pits” (NOAA 2019f). Gray whales are primarily found in the shallow coastal waters of the North Pacific Ocean. They migrate from summer feeding grounds in the northern Bering and Chukchi seas and the norther Pacific coast, to winter breeding and calving areas off the coast of Baja California, Mexico.

The eastern north Pacific group of gray whales was removed from the ESA as a threatened or endangered species after 1994. The eastern north Pacific group has human influenced mortality rate falling below the PBR, and is therefore not listed as a strategic stock under the MMPA. They do not currently have a formal status under the MMPA (NOAA 2019a)

Gray whales are periodically, but not regularly sighted within the Los Angeles and Long Beach harbor area. No Gray whales were sighted during the 2013 to 2014 survey or the 2008 year survey. One small gray whale, and later a dead gray whale was observed inside the harbor areas during the 2000 year survey (MEC 2002, SEIC

2010, MBC 2016).

Section 4 Type of Incidental Taking Authorization Requested

Take Authorization Request The USCG requests authorization form the NMFS, under Section 101 (a)(5)(D) of the MMPA, for incidental take by Level B harassment (as defined by Title 50 Code of Federal Regulations, Part 216.3) of small numbers of marine mammals, specifically California sea lions, Pacific harbor seals, bottlenose dolphin, short-beaked common dolphin, and Gray whales during the installation of a wharf extension at USCG Base Los Angeles/Long Beach. With implementation of the measures summarized in Section 10: Mitigation Measures, no Level A harassment is anticipated. The USCG requests an Incidental Harassment Authorization (IHA) for the incidental take of marine mammals as described in this application. The USCG may request an annual renewal of the IHA if the project is not completed within the authorized year. The USCG is not requesting a multi-year Letter of Authorization (LOA) at this time, as the activities described in this request are not expected to rise to the level of injury or death, which would require an LOA.

A detailed description of the acoustic exposure assessment methodology used to quantify potential exposures to marine mammals resulting from underwater and airborne noise generated during pile driving can be found in Section 5: Take Estimates of Marine Mammals. The methodology used generates conservative take estimates because all animals are assumed to be exposed 100 percent of the time. Temporary behavioral responses are expected to occur as a result of the Base LA/LB OPC Homeport project; however, the extent of the response would depend on the species, received level of sound, and distance from the work area.

Method of Take The Base LA/LB OPC Homeport project has the potential to result in Level B incidental take of marine mammals due to underwater and airborne noise disturbance during the driving of new piles to extend the existing wharf at Base LA/LB. This evaluation assumes underwater noise will encompass all take. Airborne take is therefore not separated out so as to avoid doubling the take estimate due to overlap. Level A harassment is not anticipated with mitigation measures described in Section 10: Mitigation Measures.

Section 5 Take Estimates for Marine Mammals

Fundamentals of Sound Sound levels often are often expressed in decibels (dB). A decibel is commonly used to describe the magnitude of a sound pressure, and is a logarithmic measure of the sound strength. All sound levels in this document are in decibels referenced to a sound pressure of 1 micropascal (dB re: 1 μPa), which is used for underwater noise.

The reference pressure in water is different than the reference pressure in air, and therefore decibels in water and in air cannot be directly compared to each other. Sound levels in air are rarely as high as sound levels measured in water.

Most sounds, including the sound of a pile driving strike, are composed of many different frequencies.

Underwater sound levels are not weighted and measure all frequencies, which may extend below and above the audible range of many organisms. In comparison, airborne sound is often weighted to correspond to the way humans hear certain frequencies.

In-water construction activities under the proposed project would include impact pile driving, which produces impulsive sounds. Impulsive sounds are typically transient, brief (less than 1 second), broadband, and consist of high peak sound pressure with rapid rise time and rapid decay. They can occur in repetition or as a single event. Examples of impulsive sound sources include explosives, gunshots, seismic airguns, and impact pile drivers.

The metrics to describe underwater sound include its peak sound pressure level, sound exposure level, and root mean square. These metrics can be defined as:

Peak Sound Pressure Level (Peak SPL or LPEAK): Peak SPL is the instantaneous maximum sound pressure within a single pile strike. Peak SPL is a primary metric used to measure underwater sound and to describe potential effects from pile driving on marine mammals and fish.

Sound Exposure Level (SEL): The SEL is a measure of sound level that takes into account the duration of the signal. For a pile strike, the SEL characterizes the total sound energy during a single strike normalized to one second. The SEL is the constant sound level in one second, which has the same amount of acoustic energy as the original time-varying sound (i.e., the total energy of an event). For a single pile strike, the SEL is typically 25 dB less than the Peak SPL.

Cumulative Sound Exposure Level (SELcum): The installation of a pile or multiple piles throughout a day can involve hundred or even thousands of pile strikes. The Cumulative SEL represents the total sound energy associated with a series of pile strike events, such as the total pile strikes throughout the day. Cumulative SEL can be estimated from the single-strike SEL and the total number of strikes during the day.

Root Mean Square Sound Pressure Level (RMS): The RMS can represent the average sound energy of a single strike. The RMS is the square root of the energy divided by the impulse duration.

A pile strike can be characterized by its Peak SPL, RMS, and SEL. For a single pile strike, the Peak SPL will be the highest value and the SEL will be the lowest. Peak levels are generally 10 to 20 dB higher than RMS levels.

Applicable Noise Criteria The NMFS has issued acoustic thresholds for five marine mammal functional hearing groups (as updated in 2016 and revised in 2018). The NMFS guidance includes noise thresholds for Level A Harassment that are based on injury to an animal’s hearing, or onset of permanent threshold shift (PTS). For impact pile driving, the NMFS has developed the dual thresholds of Peak SEL and SELcum. There is also a SELcum injury threshold associated with vibratory pile driving.

The threshold expressed in the SELcum metric accounts for the level and duration of exposure, both of which are factors that contribute to the potential for a noise source to induce hearing loss. The threshold for pile driving is the total duration sound exposure within a 24-hour accumulation period (or less than 24 hours, if the period over which the activity occurs is less than 24 hours). This method assumes the receiver (animal) remains stationary and is neither attracted or avoids the source (NMFS 2018b).

The NMFS also has issued noise thresholds for Level B Behavior Harassment levels that are still applicable.

The Level B thresholds are based on disturbance to marine mammals by disruption of behavioral patterns, and their metric criteria is expressed in RMS. Thresholds based on the RMS metric do not consider the duration of exposure.

Both the Level A and Level B noise thresholds are different for impact pile driving and for vibratory pile driving.

The Level A and Level B noise thresholds are summarized in Table 5-1 below.

Table 5-1: Marine Mammal Injury and Disturbance Thresholds

Functional Hearing Group

Underwater Noise Thresholds Impulsive Sound

Impact Pile Driving Non-Impulsive Sound Vibratory Pile Driving

Auditory Injury Level A

Threshold (PTS)

Behavioral Disturbance

Level B Threshold

Auditory Injury

Level A Threshold

(PTS)

Behavioral Disturbance

Level B Threshold dB Peak dB SELcum dB RMS dB SELcum dB RMS Low-Frequency

Cetaceans 219 183 160 199 120

Mid-Frequency Cetaceans 230 185 160 198 120

High-Frequency Cetaceans 202 155 160 173 120

Phocid Pinnipeds (seals) 218 185 160 201 120

Otariid Pinnipeds (sea lions) 232 203 160 219 120

Notes:

Low-frequency Cetaceans = baleen whales (includes humpback, Northern minke, Sei, gray, blue) Mid-frequency Cetaceans = dolphins, toothed whales, beaked whales, bottle nose whales (includes sperm whale, killer whale, bottlenose dolphin, Pacific White-sided dolphin) High-frequency Cetaceans = true porpoises, river dolphins, cephalorhynchid. (Dall’s Porpoise) Phocid Pinnipeds = true seals (harbor seal, Northern elephant sea, ribbon seal) Otariid Pinnipeds = sea lions, fur seals (California and Stellars sea lion, northern fur seal)

Estimation of Pile Driving Sound The source of underwater sound produced during construction of the proposed project will be impact pile driving.

Pile extraction and other underwater demolition activities are not anticipated. A final design contractor has not been selected at this time. A solicitation for a design-build team will occur prior to project pile driving. The design-build team will determine final project design parameters within a set of proscribed limitations. The final number and type of piles have not been confirmed at this time. Because the pile types have not been determined, this noise analysis has evaluated two potential pile driving types: 16-inch by 16-inch concrete and 30-inch round concrete piles. The final type and size of piles will be determined during final design of the proposed project. The maximum number of piles to be driven is estimated to be up to six per day. The number of piles driven per day could vary for different project elements and is subject to change based on work conditions at the time. Similarly, the substrate below the wharf extension is not known at this time. The substrate type may be stiff clay, dense silty sand, or hard clay. Geotechnical boring to determine ground type will be completed prior to final design and pile driving by the design build contractor. A worst case scenario has been evaluated to provide the maximum number of strikes versus ground type. A variety of pile driving machine models have been evaluated, and the maximum number of strikes dependent on pile driving machine has likewise been estimated. Once the wharf extension has been completed, fender piles would be driven at a later date. The precise location and design of these piles would also be determined by the design build team. Addition of these piles has been included in all take estimates. Section 2 provides further discussion of pile driving quantities.

Table 5-2 provides the types and sizes of piles, number of piles per day, and number of strikes per pile for the most intensive scenario. The number of piles driven each day and the number of pile strikes are conservative estimates of the number of impact piles under the proposed project.

Table 5-2: Summary of Potential Pile Driving Activity

Pile Type and Size

Pile Driving Method (Impact or Vibratory) Number of Days of

Pile Driving Maximum Number of Piles per Day Number of Strikes per Pile 16-inch Concrete Impact 17 6 1,564 30-inch Concrete Impact 9 6 1,748 Concrete Fender (size tbd) Impact 21 6 Maximum 1,748

The timing of pile strikes will be limited by several restrictions to avoid and minimize noise impacts (see Section 10 Mitigation). In-water pile driving will occur between September 1 and April 14, to avoid the nesting season of the California least tern. Pile driving will occur only during daylight hours, when visual marine mammal monitoring can be conducted. Pile driving will only occur 15 minutes after sunrise at the earliest to 15 minutes before sunset at the latest, to allow the visual monitors time to complete their pre- and post-construction surveys.

5.3.1 Underwater Noise from Impact Pile Driving

Potential underwater noise effects on marine mammals have been evaluated by estimating the distances from the construction activity under the proposed project to the Level A and Level B Harassment noise thresholds.

These distances to the noise thresholds are called isopleths. The isopleth distances can be used to estimate the area within which underwater noise levels are above the NMFS noise thresholds.

5.3.1.1. Underwater Noise Modeling

The NMFS has accepted the practical spreading loss model to estimate transmission loss of sound through water (NMFS 2012). The practical spreading loss model includes both spreading loss and attenuation loss of sound levels with distance. Spreading loss represents a regular weakening of sound as it spreads from the source, while attenuation loss includes the effects of absorption and scattering.

To estimate distances associated with the PTS onset thresholds for Level A Harassment, the NMFS has provided the User Spreadsheet Tool (2018c). The User Spreadsheet Tool is an Excel spreadsheet that is based on the practical spreading loss model. The NMFS User Spreadsheet Tool consists of twelve color-coded worksheets or tabs. Spreadsheet Tab E.1, Impact Pile Driving, is the custom tab for impact pile driving with input values specific for impact pile driving activities.

For impulsive sounds such as impact pile driving, the User Spreadsheet Tool evaluates both Peak SPL and SELcum thresholds. When evaluating impulsive sources that have dual metric thresholds (i.e., SELcum and Peak), users should rely upon whichever metric yields the largest isopleth for a particular marine mammal hearing group (NMFS 2018b).

To evaluate the Level B Harassment behavioral thresholds, a manual version of the practical spreading loss model has been used. In the absence of data on site-specific attenuation rates, an attenuation rate of 4.5 dB per doubling of distance should be used for all projects (Caltrans 2015, WSDOT 2019). The basic practical spreading loss model for a 4.5 dB per doubling of distance is provided in the equation below.

TL = F * Log(D1/D2)

TL = Transmission Loss, which is the amount of sound reduction between two distances. As applied here, TL is a negative number.

D1 = distance where the sound level is known or measured, such as the reference distance of 10 meters for impact pile driving D2 = distance where the sound level is to be estimated, such as the isopleth distance to the noise threshold F = Attenuation Factor (F=15 for attenuation of 4.5 dB per doubling of distance)

To calculate the distance at which the threshold noise levels will be reached, solve for D2 in the equation below

D2 = D1 * 10(TL/15)

5.3.1.2. Modeling Assumptions

Underwater sounds from impact pile driving can be estimated from the type of pile driver (impact or vibratory), type of pile (concrete, steel, or wood), size of pile, number of pile strikes per day, and sound propagation over distance. The proposed project anticipates either 16-inch or 30-inch concrete piles, to be driven by an impact hammer (Table 5-2). Underwater sound levels have been estimated for both 16-inch and 30-inch concrete piles.

Pile Driving Sound Levels Underwater sound from pile driving varies depending on the different types and diameters of piles, types of hammers, and different types of substrates. Because underwater sound monitoring has not been conducted at the project site, the estimation of underwater sound levels has been based on acoustic data from pile driving measured at similar projects in California and other coastal waters (Caltrans 2015).

The type and size of pile, and the method of pile driving can affect the underwater sound generated during pile driving events. A vibratory hammer produces sound energy that is spread out over time and is generally 10 to 20 dB lower than impact pile driving. Sound pressures associated with concrete piles are lower than comparably sized steel piles. Other factors affecting underwater sound include water depth, tidal conditions or currents, sound attenuation systems such as bubble curtains, and geotechnical conditions (Caltrans 2015).

The first step is to determine the peak, RMS, and SEL levels for a single strike of both 16-inch and 30-inch concrete piles. Because site-specific data are not available, reference sound levels are based on measured sound levels of similar piles at a specific distance. Reference sound levels from pile driving are reported at positions close to the pile, usually at a fixed distance of 10 meters (33 feet) from the pile.

Reference sound levels for similar types and sizes of piles are available from underwater sound monitoring data conducted at other projects in California and other coastal waters. Caltrans provides a detailed summary of underwater sound levels for various types of piles and conditions in its Compendium of Pile Driving Sound Data in Appendix I of its Technical Guidance (Caltrans 2015).

The reference sound levels for the 16-inch concrete piles have been estimated from the highest of the sound measurements of 16-inch concrete piles at the Concord Naval Weapons Station (NWS) in California and the

16.5 inch concrete piles at the Kawaihae Small Boat Harbor in Hawaii (Caltrans 2015). Based on these measured sound levels, the reference sound levels have been assumed to be 192 dB Peak, 173 dB RMS, and 163 dB SEL for a single-strike of a 16-inch concrete pile under the proposed project.

The reference sound levels for the 30-inch concrete piles have been estimated from the highest of the sound measurements of 24-inch concrete piles in California and 30-inch concrete piles at the Choctawhatchee Bridge in Florida. Based on these measured sound levels, the reference sound levels have been assumed to be 192 dB Peak, 176 dB RMS, and 166 dB SEL for a single-strike of a 30-inch concrete pile under the proposed project.

Bubble Curtain The proposed project will include an air bubble curtain to reduce underwater noise from impact pile driving.

Bubble curtains infuse the area surrounding the pile with air bubbles, creating a bubble screen that inhibits the propagation of underwater sound from the pile.

Results on the effectiveness of bubble curtains in reducing sound pressure waves are varied. A Caltrans review of the effectiveness of bubble curtains found that the data generally indicate that an air bubble curtain used on a steel or concrete pile with a maximum cross-section dimension of 24 inches or less will provide approximately 5 dB of sound reduction (Caltrans 2015). For a mid-sized steel pile (with a dimension greater than 24 but less than 48 inches), the data indicates that an air bubble curtain will provide about 10 dB of sound reduction. For larger piles (with a dimension of greater than 48 inches) about 20 dB of sound reduction is indicated.

Proper design and implementation of the air bubble curtain are key factors in the effectiveness of this strategy.

Because of the uncertainties associated with degree of attenuation that would be provided by an air bubble curtain, it is recommended that attenuation assumed for any attenuation device be limited to 5 dB (Caltrans 2015). For the proposed project, the proposed bubble curtain is assumed to reduce the reference sound levels for pile driving sound by 5 dB, which is a conservative assumption.

Number of Impact Pile Strikes The NMFS Level A thresholds account for the level and duration of exposure, and are based on the total duration sound exposure within a 24-hour accumulation period. The 24-hour cumulative sound level is calculated from the reference sound level of a single strike and the total number of pile strikes in a day. The total pile strikes are calculated from the number of strikes per pile and the number of piles per day, which are presented in Table 5-2.

In comparison, the NMFS Level B behavioral harassment thresholds are based on the RMS metric, which does not consider the duration of exposure and the number of pile strikes.

Sound Propagation Underwater sound propagation for most pile driving projects in shallow water can involve the direct transmission from the source to the receiver, reflections from the surface and the bottom, and the potential for sound energy that is re-radiated from the ground to reach the receiver. Underwater sound propagation can be evaluated from site-specific sound measurements, or from conservative assumptions when activity-specific information is unavailable.

Because site-specific data on sound propagation is not available for the proposed project site, sound propagation has been estimated from the NMFS default values. NMFS typically recommends the default propagation value of practical spreading (15 log R) for projects occurring in shallow, coastal areas (e.g., pile driving). Sound is assumed to diminish at a rate of 4.5 per doubling of distance from the pile, and is considered a conservative approach.

Marine Mammal Auditory Weighing Functions Auditory weighting functions take into account what is known about marine mammal hearing sensitivity and susceptibility to noise-induced hearing loss, and can be applied to a sound-level measurement to account for frequency-dependent hearing. The NMFS User Spreadsheet Tool incorporates marine mammal auditory weighting functions. For impact pile driving, the default Weighing Factor Adjustment (WFA) is 2 kHz (NMFS 2018b).

Modeling Input Summary Table 5-3 presents the modeling input data for estimating the underwater sound levels under the proposed project. The exact size of piles and number of pile strikes are not yet known early in the design process, so the input data in Table 5-3 are worst-case estimates to provide a conservative approach.

Table 5-3: Data Used to Estimate Underwater Sound from Pile Driving

16-inch Concrete

Impact Pile Driving Sheet E.1

30-inch Concrete Impact Pile Driving

Sheet E.1 Source Weighing Factor Adjustment (WFA) 2 2 NMFS default Source Peak Level(1) 187 187 Caltrans 2015 Source RMS(1) 168 171 Caltrans 2015 Source SEL(1) 158 161 Caltrans 2015 Number of strikes per pile 1,564 1,748 Number of piles per day 6 6 Propagation (xLogR) 15 15 NMFS default Distance of single strike SEL measurement (meters) 10 10 Caltrans 2015

Notes:

1) A 5‐dB reduction was assumed for impact driving with the use of bubble curtains (Caltrans 2015)

5.3.1.3. Estimation of Pile Driving Noise

Table 5-4 provides the estimated distances (isopleths) to the Level A and Level B noise thresholds under the proposed project. Appendix A provides copies of the NMFS User Spreadsheet Tools. Figures 3 and 4 provide an aerial reference for the distances outlined in Table 5-4.

Table 5-4: Estimated Distances of Level A and B Noise Thresholds

Level A Noise Thresholds - Impact Pile Driving

Pile Type

Low- Frequency Cetaceans

Mid- Frequency Cetaceans

High- Frequency Cetaceans

Phocid Pinnipeds

Otariid Pinnipeds

Level B 160 dB Impact Piles

Level B 120 dB

Vibratory Piles

SELcum Threshold 183 185 155 185 203 -- --

RMS

Threshold -- -- -- -- -- 160 120

16-Inch Concrete

Isopleth to threshold (meters)

95.7 3.4 114.0 51.2 3.7 34.1 N/A

30-Inch Concrete

Isopleth to threshold (meters)

163.4 5.8 194.6 87.4 6.4 54.1 N/A

Notes:

1) A 5‐dB reduction was assumed for impact driving with the use of bubble curtains (Caltrans 2015)

Underwater noise from impact pile driving under the proposed project is estimated to exceed both the Level A (injury) and Level B (behavioral) noise thresholds. The proposed project will include an air bubble curtain during construction to reduce underwater noise from impact pile driving, which has reduced the distances over which Level A and Level B harassment would occur. Mitigation measures to reduce underwater noise impacts are identified in Section 10: Mitigation Measures.

Figure 3: Distances to Level A Noise Thresholds.

Figure 4: Distance to Level B Noise Thresholds

5.3.2 Airborne Noise

Pile driving will generate airborne noise that may result in behavioral disturbance to pinnipeds that are hauled-out or otherwise surfaced. Similar to underwater noise, the practical spreading model is used to estimate the extent of sound levels that may result in Level B harassment of marine mammals. Distance to NMFS thresholds was calculated with a 20 log10 attenuation rate.

Measurements taken during the Naval Base Kitsap at Bangor Test Pile Program Final Marine Mammal Monitoring Report (HDR 2012) were utilized for estimation of airborne noise due to vibratory and impact driving.

The greatest unweighted maximum noise level (Lmax) measurement was 102 dB, with the average Lmax being 97 dB at 50 feet (15 meters). Impact driving noise was at the greatest Lmax at 112 dB, with the average Lmax at 103 dB at 50 feet (15 meters).

Table 5-5 provides Lmax distance levels for conservatively estimating the distance to NMFS harassment thresholds. Airborne noise is not considered further so as to not double count potential take that may occur due to underwater noise.

Table 5-5 Extent of Sound Pressure Levels for Airborne Noise

Activity Distance Area 100 dB 90 dB 100 dB 90 dB

Vibratory Extraction and Driving 20 meters 60 meters 0.001 km2 0.011 km2 Impact Driving 60 meters 190 meters 0.011 km2 0.113 km2

Note: dB = decibel

Description and Estimation of Take The USCG is seeking authorization for exposure of marine mammals to Level B harassment that may result from pile driving activities associated with the LA/LB OPC Homeport wharf extension. Take is expected to be limited to behavioral effects on individuals, with no effect on species populations. Any effect on an individual of a marine mammal species is anticipated to be limited to short-term disturbance of normal behavior, or temporary displacement of animals from the zone of responsiveness. There are limited estimates of marine mammal density for the Los Angeles and Long Beach harbors. Biological surveys of the harbors were completed across 2013 and 2014 to provide a biological baseline (MBC 2016).

Marine mammal monitoring will ensure that no cetaceans or pinnipeds are present in the relevant Level A harassment zones during pile driving.

Population estimates for take are based on biological baseline surveys performed for the Los Angeles and Long Beach harbors in 2000, 2008, and 2013-2014 (MEC 2002, SEIC 2010, MBC 2016). The highest population observation in the survey zones surrounding the Base LA/LB for each species was assumed to be the maximum number of individuals that would be affected on any given day. This is a conservative approach that seeks to overestimate Level B take, as the Base LA/LB wharf is not in an area that appears to be highly travelled or frequented by marine mammals.

5.4.1 California Sea Lion Take

Biological baseline studies for the Los Angeles and Long Beach provided counts for California Sea Lions (MEC 2002, SEIC 2010, MBC 2016). Surveys in 2000 and 2008 collected incidental observations primarily during birding surveys, but also during the course of other surveys for water quality, benthic invertebrate sampling,…