9.12_-_Hydroacoustic_Monitoring_Plan_May_2023.pdf

Hydroacoustic Monitoring Plan

Murray Street Bridge (# 36C-0108) Seismic Retrofit Project

MAY 2023

Murray Street Bridge

Santa Cruz Small Craft Harbor

City of Santa Cruz

Santa Cruz County, CA

Federal Project Number STPLX-5025 (048)

Prepared for:

CITY OF SANTA CRUZ

809 Center Street

Santa Cruz, CA 95060

Prepared by:

DUDEK

725 Front Street #400 Santa Cruz, California 95060

INTENTIONALLY LEFT BLANK

MURRAY STREET BRIDGE SEISMIC RETROFIT PROJECT / HYDROACOUSTIC MONITORING PLAN

12133 i MAY 2023

Table of Contents

SECTION PAGE NO.

1 Project Overview

1.1 Project Setting and Purpose

1.2 Project Description

1.3 Pile Removal and Installation

2 Regulatory, Guidelines and Requirements

2.1 Marine Wildlife Protection Plan and Permit Conditions

2.1.1 Target Marine Wildlife

2.1.2 California Sea Lion

2.1.3 Harbor Seal

2.1.4 Southern Sea Otter

2.2 Marine Wildlife Protection Measures

3 Monitoring Methodology

3.1 Contractor Requirements

3.2 Sound Monitoring Equipment and Monitoring Requirements

3.3 Pile Driving Measurements for Fish and Marine Mammal Consultations

3.4 Background Underwater Sound Levels

3.5 Flow-Induced Underwater Noise

3.6 In-Air Noise Measurements

3.7 Calibration

3.8 Sound Attenuation Monitoring

3.9 Signal Processing

3.9.1 Impact Pile Driving

3.9.2 Vibratory Pile Driving

4 Analysis

4.1 Impact Pile Driving

4.2 Vibratory Pile Driving

5 Reporting

6 References ii MAY 2023

TABLE(S)

Table 1. Summary of Bridge Pile Types and Numbers

Table 2. NOAA-Fisheries Marine Mammal Protection Underwater Level A Thresholds

Table 3. Summary of Monitoring Requirement for Piles to be Installed or Removed

Table 4. Example Equipment for Underwater and In-Air Sound Monitoring

FIGURE(S)

Figure 1 Project Location

Figure 2 Bridge Cross Section and Bent Locations

APPENDICES

A – Calculation of Cumulative SEL

B – Calculation of a Cumulative Distribution Function and Plot for Background Sound Level Analysis (NOAA 2012a)

C – Example Hydroacoustic Monitoring Log

1 MAY 2023

1 Project Overview

1.1 Project Setting and Purpose

The Murray Street Bridge Seismic Retrofit Project (project) is located at the eastern edge of the City of Santa Cruz in the county of Santa Cruz. The project area includes the Murray Street Bridge which spans the Santa Cruz Small

Craft Harbor, portions of lands within the Santa Cruz Port District harbor area, portions of the harbor waters, and the area along the Murray Street right-of-way west of Lake Avenue.

The proposed project consists of a seismic retrofit of the existing Murray Street Bridge which spans the Santa Cruz

Small Craft Harbor in Santa Cruz, California. The purpose of the project is to provide additional vertical support to the bridge and resistance to lateral seismic forces by installing additional pilings and supplemental structural elements. The project also includes minor modifications to replace deficient bridge barriers (widening shoulders to standard widths and replacement and improvement of sidewalks and railings) and relocation of Santa Cruz County

Sanitation District’s East Cliff Transmission Main (ECTM).

1.2 Project Description

The project includes both on-land and in-water construction activities. On-land construction activities include demolition, pile and anchor installation outside of the waterway, bridge construction, contractor staging, installation of a temporary bypass sewer line, and ECTM relocation. In-water construction activities include removal and temporary relocation of docks to accommodate construction access; potential installation of piles for a temporary construction trestle from the bridge; pile driving; transport of materials; and replacement of harbor docks upon completion of the bridge seismic retrofit project. All project-related construction activities that result in noise and vibration may result in incidental take (harassment) of marine mammals present in the area at the time of construction.

The Murray Street Bridge Retrofit project is tentatively proposed for construction in nine phases over an approximate 2-year, 4-month period, commencing in the summer /fall of 2023. In-water activity will occur in over an approximate 4-month period over two years. Due to in-water work timing restrictions to protect federally-listed salmonids, all in-water construction activities including pile removal/installation would occur during the period from

July 1 to mid-November unless otherwise permitted by NOAA-Fisheries.

Of particular interest as it pertains to the hydroacoustic monitoring and this Plan, are the in-water construction activities which include removal and temporary relocation of docks to accommodate construction access; potential installation of piles for a construction trestle from the bridge; pile driving; transport of materials; and replacement of harbor docks upon completion of the bridge seismic retrofit project. The most intense of the in-water activities would be the removal and installation of piles. Overall, the installation of piles is expected to take a total of approximately 1.5 days for each 30-inch pile and 4 days for 8 16-inch piles for a total of 31 days. The installation of these piles requires the use of a crane(s), a drilling rig, a pile driver, excavation and earthmoving equipment, concrete trucks and pumps, concrete vibrators, supply trucks, welding equipment, and other machinery.

2 MAY 2023

1.3 Pile Removal and Installation

The bridge seismic retrofit will include removal and installation of piles as summarized in Table 1, including on-land piles for the bridge structure and associated retaining walls. The installation of new piles will include a total of 86 bridge piles. Eight on-land piles will be added on the north side of the bridge to support relocation of the ECTM. In addition, 4 14-inch concrete piles would be removed at Bent 6 and 35 14-inch concrete piles would be removed at

Docks FF and BY to accommodate project construction with reinstallation of the dock piles upon completion of construction. A total of 115 on-land piles will be driven to support three on-land retaining walls.

Table 1. Summary of Bridge Pile Types and Numbers

Location Number Pile Type

In Water

• Removal - Bridge Bridge Bent 6 4 14-inch P/C Concrete

• Remove Dock FF & TT Piles Dock FF & T 35 14-inch P/C Concrete

Total In Water Removal 39

• Install New Permanent Bridge Piles Bridge Bent 4 2 30-inch CIDH1

Bridge Bent 5 4 30-inch CISS

Bridge Bent 6 4 30-inch CISS

Bent 7 4 30-inch CISS

Bent 8 4 30-inch CISS

Bent 9 8 16-inch CISS

Bridge Subtotal 26

• Install New Dock FF & T Piles 35 14-inch P/C Concrete

Total In Water Bridge Pile Installation 61

On Land

• Install New Permanent Bridge Piles Abutment 1 4 16-inch CISS

Bridge Bent 2 2 30-inch CIDH1

Bridge Bent 3 South 2 30-inch CIDH1

Bridge Bent 3 North 1 30-inch CIDH1

Bridge Bent 4 2 30-inch CIDH

Abutment 10 8 16-inch CISS

Anchor Piles 2 96-inch CIDH

Bridge Subtotal 25

• Install New Retaining Wall Piles Retaining Wall 11 20 24-inch CISS

Retaining Wall 17 38 24-inch CISS

Retaining Wall 18 32 24-inch CISS

Total On Land Bridge Pile Installation 115

Optional In Water

• Install and Remove Trestle:

Install Temporary Piles Adjacent to Bridge 120 12-inch steel pipe piles

Remove Temporary Piles Adjacent to Bridge 120 12-inch steel pipe piles

Total Optional In-Water Pile Installation 240

Note:

1 Permanent casing will be driven or vibrated into place.

2 To support a relocation of a sewer line that is under consideration.

3 MAY 2023

Installation of new bridge support piles, following the demolition and removal of existing piles, would occur at Bent

6. Bents 5 through 8 will install cast-in-steel-shell (CISS) piles within the waterway by driving 30-inch steel casings either to refusal at rock or into a shaft drilled within rock (depending on the location). The installation of new piles at Bents 5 through 8 will include two piles on each side for a total of 16 piles in the water (and 10 additional piles at Bents 4 and 9 that are partially in the water). Based on the geotechnical site characteristics, permanent bridge piles will be partially or entirely vibrated into the Harbor substrate rather than driving them entirely by means of an impact-hammer pile-driver. A vibratory hammer would be used to start driving all sheet piles, but an impact hammer may be required to complete driving depending on the density of subsurface materials.

If a temporary trestle is constructed to facilitate installation of the permanent bridge piles, it is estimated that 120

12-inch steel piles or 72 20-inch steel piles would be installed and removed upon completion of construction.

2 Regulatory, Guidelines and Requirements

National Oceanic and Atmospheric Administration - Fisheries and National Marine Fisheries Service (NOAA-

Fisheries/NMFS) joined with Caltrans, other regulatory agencies and researchers to form the Fisheries

Hydroacoustic Working Group (FHWG) with the intent to provide guidance and establish criteria for the evaluation.

The FHWG and NOAA-Fisheries issued interim guidance on hydroacoustic levels resulting from pile driving activities and subsequently agreed upon a dual metric criterion for the onset of physical injury (Level A harassment) of 206 dB re: 1µPa Peak for any single strike and an accumulated sound exposure level (cSEL1) of 187 dB re: 1µPa2s. for all fish greater than 2 grams in size. The agreed upon criteria for fish less than 2 grams maintains the 206 dB Peak single-strike threshold and lowers the accumulated cSEL limit to 183 dB re: 1µPa2s. In addition, NOAA-Fisheries uses a threshold of 150 dB re: 1µPa RMS average sound pressure level as an indication for the onset of behavioral disturbance responses (Level B harassment) for salmonids and green sturgeon is appropriate, until new information indicates otherwise; and 150 dB re: 1µPa2s cSEL or below, resulting from an individual pile strike is considered to be “effective quiet”, or the level at/below which the accumulated energy from multiple strikes would not contribute to injury, regardless of the number of strikes.

In 2016 NOAA-Fisheries issued guidance on underwater thresholds for onset of permanent threshold shifts (PTS) or internal injury for marine mammals, which was updated and incorporated in the “2018 Revision to: Technical

Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0)”. These underwater thresholds marine mammal protection are provided below in Table 2.

1 The calculation method for cumulative sound exposure level (cSEL) is shown in Appendix A (NOAA 2012a)

4 MAY 2023

NOAA-Fisheries indicates that marine mammals are likely to be behaviorally harasses in a manner that would qualify as Level B harassment when exposed to underwater noise levels above received levels of 120 dB 1µPa RMS for continuous sources (e.g., vibratory pile driving, drilling), and above received levels of 160 dB 1µPa RMS for non-explosive, impulsive sources (e.g., seismic air guns, impact pile driving) or intermittent sources (e.g., scientific, non-tactical sonar).

For airborne sound, harbor seals are considered to be behaviorally harassed (Level B harassment) when exposed to received levels equal to, or greater than 90 dB re: 20 µPa RMS, and all other pinnipeds would be considered harassed when exposed to received levels equal to, or greater than 100 dB re: 20 µPa RMS.

2.1 Marine Wildlife Protection Plan and Permit

Conditions

A Marine Mammal Monitoring Plan (MMMP) (City of Santa Cruz, Dudek 2022) was drafted to address marine mammal species potentially present within the construction area and identify mitigation measures for the avoidance/minimization of detrimental effects of the project on target marine mammals. The document was prepared in support of the City’s Incidental Harassment Authorization (IHA) application submitted to the National

Oceanic and Atmospheric Administration (NOAA) Fisheries. The marine wildlife protection measures (Section 2.2) specified in the Marne Wildlife Protection Plan (MWPP) (City of Santa Cruz, Dudek 2023) replace those in the MMMP and IHA Application because they incorporate additional measures from Special Condition 5 of the California

Coastal Commission’s coastal development permit (CDP 3-22-0165), the proposed IHA (88 FR 12316-12334), the

Streambed Alteration Agreement with the California Department of Fish and Wildlife (CDFW) (EPIMS-SCR-23133-

R3), and informal consultation with US Fish & Wildlife Service (USFWS) to maximize the project’s protection of these species. The marine wildlife protection plan attempts to combine the various overlapping measures from the above sources related to marine mammals and reconciles conflicts or discrepancies between the various agencies to ensure protection of marine mammals and feasible implementation of requirements.

Table 2. NOAA-Fisheries Marine Mammal Protection Underwater Level A Thresholds

Hearing Group (Hearing Range/Weighting)

Accumulated SEL (cSEL) Threshold Peak Threshold Impulsive1 Non-impulsive2 Impulsive1

Low-Frequency Cetaceans (LF 7 Hz. to 35 kHz.) 183 dB 199 dB 219 dB

Mid-Frequency Cetaceans (MF 150 Hz. to 160 kHz.) 185 dB 198 dB 230 dB

High-Frequency Cetaceans (HF 275 Hz. to 160 kHz.) 155 dB 173 dB 202 dB

Phocid Pinnipeds (PW 50 Hz. to 86kHz.) 185 dB 201 dB 218 dB

Otariid Pinnipeds (OW 60 Hz. 39 kHz.) 203 dB 219 dB 232 dB

Source: NOAA Fisheries 2018.

Notes: dB = decibel; cSEL = cumulative sound exposure level over a 24-hour period, with a reference value of 1µPa2s; Peak = peak unweighted sound pressure level with reference to 1µPa

1 – Permanent Threshold Shift (PTS)/injury dual metric threshold for impulsive sources such as impact pile driving, use whichever metric results in the largest isopleth (e.g., seismic air guns, impact pile driving).

2 – Permanent Threshold Shift (PTS)/injury threshold for non-impulsive sources (e.g., vibratory pile driving, drilling).

5 MAY 2023

2.1.1 Target Marine Wildlife

Three marine mammals are known to occur, at least occasionally, within the Santa Cruz Small Craft Harbor (Harbor):

southern sea otter (Enhydra lutris nereis), harbor seal (Phoca vitulina richardii); and the California sea lion

(Zalophus californianus). All marine mammals are protected under the Marine Mammal Protection Act, and the southern sea otter has additional protection under the federal Endangered Species Act. The docks and other features within the Harbor are haul-out sites for harbor seal and California sea lion. The open water of the project site and surrounding vicinity provides habitat for the southern sea otter, the harbor seal, and California sea lion.

Additional marine mammal species including bottlenose dolphins (Tursiops truncatus) and harbor porpoise

(Phocoena phocoena) may occur in the project vicinity towards the mouth of the harbor, however surveys have not detected these species within the proposed buffer zone and both species appear to have stable or increasing population trends.

2.1.2 California Sea Lion

California sea lions are not federally-listed under the Endangered Species Act but receive protection under the

Marine Mammal Protection Act. They occur from California to Canada. California sea lions are known to occur within the Harbor, especially near the UCSC dock and the docks of the west harbor opposite the small vessel boat yard.

The species uses the Harbor for foraging and haul-out activities, most often when fish are abundant in the area.

The Harbor does not provide mating or breeding habitat or other habitat of a similar ecological significance for the

California sea lion.

2.1.3 Harbor Seal

Harbor seals are not federally-listed under the Endangered Species Act but receive protection under the Marine

Mammal Protection Act. They occur from Mexico to Alaska. Harbor seals are known to occur in the Harbor, using the open water for foraging and the docks for haul-out activities. The numbers of harbor seals occupying the harbor are likely to be highest during late summer, fall and winter, outside of breeding (March - May) and molting (June -

July) seasons. The species is especially sensitive to disturbance, flushing readily from haul-out locations as a result of human activity. The Harbor does not provide mating or breeding habitat or other habitat of a similar ecological significance for harbor seals.

2.1.4 Southern Sea Otter

Southern sea otter is federally-listed as Threatened under the Endangered Species Act. The species occurs from

Santa Barbara to San Mateo County in California. Otters occur in the kelp forests just off the coast, where separate groupings of females and young, territorial males, and non-territorial males breed, forage, and groom in close proximity to the Harbor. The southern sea otter appears to be an incidental visitor to the Santa Cruz Small Craft

Harbor. The Harbor does not provide mating or breeding habitat for the species. According to consultation with

USFWS (2022), a USFWS Incidental Harassment Authorization (IHA) and/or incidental take permit under ESA is not required for sea otter provided the City employs the following measures during project construction: establish a stop-work zone at the 160 decibel isopleth for underwater noise and monitor to ensure no sea otters enter the area within that 160-decibel isopleth during in-water work, and employ standard construction best practices to ensure oil or other fluids associated with heavy machinery do not enter the marine environment. These are described in more detail in Section 2.2.

6 MAY 2023

2.2 Marine Wildlife Protection Measures

To avoid or minimize the potential construction-related effects to target marine mammals at or near the Murray

Street Bridge Seismic Retrofit site avoidance/minimization and other mitigation measures will be implemented in accordance with the approved Marine Mammal Monitoring Plan (City of Santa Cruz 2022), Special Condition 5 in the proposed project’s Coastal Development Permit (CDP) through the California Coastal Commission, and the proposed IHA (88 FR 12316-12334). These measures are detailed below and generally include:

• Limitation on timing of pile driving;

• Pre-construction monitoring and hydroacoustic monitoring during construction; and

• Establishment of a buffer and monitoring of noise levels.

The following measures will be implemented to avoid or minimize potential project-related effects to southern sea otters, harbor seals, California sea lions and other sensitive marine wildlife species:

1. Timing of Pile Driving. In-water pile-driving activities within Harbor waters will be limited to the period of

July 1 to mid-November to protect federally-listed salmonids, unless otherwise permitted by NOAA

Fisheries.

2. Impact Hammers. Impact hammers will not be used except in cases where vibratory hammers are not a feasible option, at the discretion of the construction contractor. The construction contractor shall install bubble curtains at all piles driven by impact hammers to reduce sound levels for fish and/or marine mammals that may be present in the area and undetected. If use of an impact hammer results in exceedance of sound thresholds, impact pile driving shall cease and the construction contractor shall revise the sound attenuation method through modifications such as changing bubble density, bubble size, or the number of bubble curtain rings employed. The construction contractor shall conduct additional sound monitoring of five piles or two days to demonstrate that compliance has been achieved, and the modified methods shall be used for the remainder of pile driving.

3. Soft Starts. At the commencement of any impact pile-driving activities, or after a break in impact hammer driving of 30 minutes or more, a soft start procedure shall be implemented. The “soft start” shall consist of an initial set of 3 strikes made by the impact hammer at 40 percent energy, followed by a one-minute waiting period, then two subsequent three-strike sets, before initiating continuous driving. The pile driver shall also employ sound dampening techniques (i.e., wooden blocks, pile cushions, and/or caps) during all impact hammer pile-driving activities. If vibratory pile-driving is used, a soft start procedure shall also be used, but would constitute a gradual ramp up of vibratory intensity as follows: An initial one-minute period of vibratory driving at 40 percent energy, followed by a one-minute waiting period, followed by a two-minute period of vibratory driving at 40 percent energy before commencing vibratory driving at full energy. The purpose of the soft-start procedure is to allow marine mammals a chance to leave the site prior to the impact hammer operating at full capacity.

4. Marine Wildlife Monitors. One or more qualified marine wildlife monitors (MWM) (equivalent to a

Protected Species Observer [PSO] as required under the IHA), approved by NOAA Fisheries and California

Coastal Commission Executive Director, will be assigned to the project as required depending on the ability for MWMs to observe the full exclusion area. MWMs shall be independent (not construction

7 MAY 2023

personnel), be dedicated to observing marine wildlife, and have no other assigned tasks during monitoring periods.

Any MWMs will be qualified wildlife biologists with experience observing marine wildlife and differentiating normal behavior from signs of distress or injury. At least one MWM must have prior experience performing these duties during construction pursuant to a NOAA Fisheries-issued IHA. Additional MWMs can substitute education or training for this experience. If three or more MWMs are required on the project site, a lead MWM with prior experience working with marine mammals during construction shall be designated.

All MWMs shall have the following qualifications: a) ability to conduct field observations and collect data according to assigned protocols; b) experience or training in the field identification of marine mammals, including the identification of behaviors; c) sufficient training, orientation, or experience with the construction operation to provide for personal safety during observations; d) writing skills sufficient to prepare a report of observations, including but not limited to the number and species of marine mammals observed; dates and times when in-water construction activities were conducted; dates, times, and reason for implementation of mitigation (or why mitigation was not implemented when required); and marine mammal behavior; and e) ability to communicate orally, by radio or in person, with project personnel to provide real-time information on marine mammals observed in the area as necessary.

5. Pre-Construction Monitoring. Prior to initiation of in-water construction, a qualified MWM (refer to

Measure 4) will conduct monitoring of marine mammals to update existing information on the animals’ occurrence in and near the project area, their movement patterns, and their use of any haul-out sites.

This preconstruction monitoring will take place at least five days prior to the start of in-water construction and will cover a period of at least one week (with at least 5 days of actual observation over a period of 4 hours each day), 2 hours in the morning at the time that construction activities would begin and 2 hours at midday, when construction activities would resume after a lunch break.

6. Pre-Construction Removal of Haul-out Sites. All known and potential haul-out sites that occur in the construction work area shall be removed, preferably to a near-by location outside of the work area prior to construction. These sites could include floating docks (i.e., Dock FF) rubber docks, or boats, such as those used by UCSC.

7. Pre-Construction Workers Training. Prior to in-water construction, the approved MWM (Measure 4) will conduct a worker’s training to instruct construction crews regarding the status and sensitivity of the target species in the area and the actions to be taken to avoid or minimize impacts in the event of a target species entering the in-water work area. New personnel joining during the project must be trained prior to commencing work.

8. In-Water Construction Biological Monitoring. Each day, before pile driving (or other loud in-water construction activity) begins, the MWM(s) (Measure 4) will survey for marine mammals for a minimum of

30 minutes within the shutdown zone (a 10-meter/32.8-foot radius area surrounding each work site where construction could cause physical disturbance to a marine mammal) and the exclusion zones (see

Measure 10 for preliminary exclusion zones, or as determined through the approved Hydroacoustic

8 MAY 2023

Testing Plan as described under Measure 11)2. The MWM(s) will also scan for target species throughout the shutdown zone and exclusion zones throughout in-water project activities, as elaborated below. At the daily conclusion of pile installation, the MWM will also conduct 30 minutes of post-pile driving activity and clearance monitoring of the exclusion zones before leaving the site, noting changes in marine mammal activity or presence after pile installation activities stop.

The qualified MWM(s) will be present during all in-water construction activities to search for target marine mammal species and halt project activities that could result in injury or mortality to these species [an estimated 8 hour/day (or for the duration of in-water construction activities each day) during the estimated 10 months of in-water activities plus an additional 16 days of on-land pile driving]. MWMs shall avoid direct physical interaction with marine mammals during construction activity. The MWM(s) should not be assigned duties apart from observing marine mammals to ensure optimal detection probability for wildlife. The MWM(s) shall have all appropriate safety and monitoring equipment (e.g., binoculars) adequate to conduct monitoring activities, and at least one MWM shall be located at an effective vantage point to observe the exclusion zone (with particular focus on the shutdown zone) without obstruction.

Multiple MWMs may be employed during periods of low or obstructed visibility and to ensure the entirety of the shutdown and exclusion zones are monitored.

9. Construction Halts. Construction halts will be enacted immediately upon detection of target marine wildlife within the exclusion zone by notifying the equipment operator, and City staff and/or the

Construction Manager shall be notified. Pile driving will be delayed until the marine mammal(s) has moved beyond the exclusion zone, verified by visual confirmation by the MWM or lack of visual sighting within the exclusion zone for 30 minutes3 following the last sighting. The monitor will record the species, numbers and behaviors of any animal(s) entering the exclusion zone after commencement of work and notify the City of Santa Cruz within 48 hours. If the shutdown zone is not entirely visible (e.g., due to darkness, fog, etc.), pile driving shall not commence or continue to proceed (if it is underway) until visual conditions have improved and the entirety of the shutdown zone is visible to the MWM(s). A halt will also be enacted if a marine mammal species for which the IHA is not authorized, or an authorized species that has surpassed the take allowance is observed within the exclusion zones.

10. Preliminary Exclusion Zones. During hydroacoustic testing in accordance with an approved Hydroacoustic

Testing Plan, the following minimum exclusion zones will be implemented for marine mammals for installation of piles:

a. During vibratory or impact hammer4 installation of concrete or steel piles, a 410-meter (1,345-foot) exclusion zone for all marine mammals other than southern sea otters.

b. During all pile installation regardless of pile type or installation methods, a 63-meter (207-foot) exclusion zone for southern sea otters.

2 The CDFW Streambed Alteration Agreement (EPIMS-SCR-23133-R3) stipulates pre-construction monitoring within a 500-foot buffer zone; given that the exclusion zone is larger than the 500-foot buffer, we have opted to include the larger survey area.

3 The IHA, Streambed Alteration Agreement, and approved MMMP stipulate a 15-minute wait time, which conflicts with the

California Coastal Commission permit. Given the conflict, the more protective option of the two (30 minutes) is specified.

4 The CDP Condition 4b applies this preliminary exclusion zone only to installation by vibratory methods. Since installation through use of impact hammers remains a possibility, this exclusion zone has been revised to include both methods to ensure protection of marine mammal species during hydroacoustic testing. The CDP Condition 4b also includes a different exclusion zone for impact hammer installation of timber piles, which is not proposed under the project and has not been included here.

9 MAY 2023

An additional non-pile driving exclusion zone will apply to in-water construction activities that do not result in loud or impulsive sounds, such as the use of heavy equipment to construct bridge abutments. For these activities, a 50-foot radius non-pile driving exclusion zone will be established.

These exclusion zones will be visibly flagged on the banks of the harbor to facilitate construction monitoring efforts. Each day, prior to the start of construction activities, the approved MWM(s) will survey the shutdown zone and exclusion zones for marine mammals.

11. Exclusion Zone Changes – Acoustical Monitoring. Acoustical monitoring will be conducted during pile driving activities according to the Hydroacoustic Testing Plan (under separate cover) to determine sound generation and propagation within the Harbor. The preliminary exclusion zone for installation of concrete and steel piles described under Measure 10 (410 meters) may be reduced or increased based on a measurement of the distance that the 160 decibel (dB) root-mean-square (RMS) sound pressure travels underwater before attenuating to the 160 dB re: 1µPa root-mean-square (RMS) threshold level and/or through the air. This shall be determined using approved in-water and in-air acoustic monitoring devices operated in accordance with the Hydroacoustic Testing Plan approved by NOAA Fisheries and the CCC

Executive Director. The City of Santa Cruz shall notify NOAA Fisheries and the CCC Executive Director in writing of a proposed change in the exclusion zone radius, and will not adjust the exclusion zone without approval from these entities. An approved MWM will operate the monitoring devices during pile driving and any other loud in-water construction activities, such as use of hydraulic tools. The devices, placed at the edge of the exclusion zone, will produce acoustic data for the duration of noise-producing activities.

An alarm would alert the monitor to sound levels approaching 160 dB re: 1µPa RMS. If the 160 dB re:

1µPa RMS threshold is exceeded at the current approved exclusion zone, the exclusion zone will be increased to the distance along the edges of the harbor where the in-water sound pressure drops below

160 dB re: 1µPa RMS. This would be a dynamic buffer and would be expected to change as project activities change (e.g., different pile types or sizes are driven or different methods are used), potentially on a daily or weekly basis. The exclusion zone may be reduced or increased based the results of the approved Hydroacoustic Testing Plan (under separate cover) but will not exceed the 160 dB re: 1µPa

RMS isopleth.

12. Underwater Acoustical Monitoring – Use of Vibratory Pile Driving Equipment. The contractor will be allowed to use vibratory driving if the contractor can demonstrate through implementation of the

Hydroacoustic Testing Plan that the 120 dB re: 1µPa RMS vibratory threshold will not be exceeded within

1,000 meters (3,281 feet) of pile driving. If this cannot be achieved, the contractor will then be required to use impact driving only and limit measured sound levels to 160 dB re: 1µPa RMS or less at 1,000 meters. The distance from the bridge to the breakwater is about 780 meters (2,559 feet). This means that the impact distance for either vibratory or impact driving has the potential to extend about 220 meters (722 feet) into Monterey Bay. These distances do not represent exclusion zones intended to prevent Level A harassment (those are described as part of Measures 10 and 11), but rather distances beyond within which Level B harassment could occur.

13. Disturbance Prohibition. No intentional hazing (e.g., disturbance, noise) will be used on eastern Pacific harbor seals, California sea lions, southern sea otters, or other state- or federally-listed threatened or endangered species. The City of Santa Cruz will contact USFWS and NOAA Fisheries as appropriate to determine the best approach for exclusion of the target species from the in-water work area and whether any changes to this wildlife protection plan may be required.

10 MAY 2023

14. Construction Monitoring Records. The approved MWM will keep a record of all observations of the target species. The record for each observation will include: a) name and location of the MWM making the observation; b) dates and times (begin and end) of all marine mammal monitoring and date and time of sighting; c) a map showing species identification and estimated number of marine mammals observed

(min/max/best estimate); d) age and sex class of each marine mammal (if possible); e) activity, distance relative to the work site, and direction of movement; f) ongoing project activities at the time of observation;

g) responses of target species to project activities; h) any wildlife behavior patterns or circumstances observed (project- or non-project related), including correlation of behavior to project-related activities (if relevant); and g) number of marine mammals observed in the shutdown and exclusion zones; and h) detailed information about implementation of any mitigation (e.g., shutdowns and delays), a description of specified actions that ensued, and resulting changes in behavior of the animal(s), if any.

Regardless of whether marine mammals are detected, daily reports should be logged which include: a) the date and time that monitored pile driving activity begins and ends; b) pile driving activities (e.g., the number and type of piles being driven and their location, the type of hammer being used (i.e. impact or vibratory) occurring during each observation period); c) weather parameters (e.g., wind speed and direction, percent sky cover, visibility, precipitation, etc.); d) ocean conditions (e.g., water level fluctuation, tide, etc.); and e) a description of other human activities in the area (e.g., fishing, diving, swimming, etc.).

Summary monitoring reports will be submitted to the City of Santa Cruz, who will forward reports to NOAA

Fisheries by December 31 of each year that in-water construction activities take place. Additionally, a summary report including copies of MWM logs shall be submitted to the City when mitigation measures such as halt or delay of pile-driving activities are implemented 5 or more times during a 7-day period, who will submit the report to the CCC Executive Director.

A draft marine mammal monitoring report will be submitted to NOAA Fisheries within 90 days after the completion of pile driving activities for each IHA, or 60 days prior to a requested date of issuance of any future IHAs for the project, or other projects at the same location, whichever comes first. The report will include all of the information specified above for recorded observations of target species. If no comments are received from NOAA Fisheries within 30 days, the draft report would be considered final. If comments are received, a final report addressing NOAA Fisheries’ comments would be required to be submitted within

30 days after receipt of comments. All MWM datasheets and/or raw sighting data would be submitted with the draft marine mammal report. Reports shall be submitted to (PR.ITP.MonitoringReports@noaa.gov).

A final report summarizing the results of monitoring activities shall be submitted to the City of Santa Cruz following completion of all construction activities, and the City shall submit final report to California Coastal

Commission and NOAA Fisheries. The report shall include daily log observations from MWMs, descriptions of any project delays or cessation of operations due to the presence in the project area of marine wildlife subject to protection, and an evaluation of monitoring protocol effectiveness all determined by the MWM(s).

15. Notification of Injury. In the event that the MWM determines that a marine mammal has been injured by project activities, all work shall cease, and the City of Santa Cruz shall be notified. The City of Santa Cruz will consult with NOAA Fisheries and USFWS depending on the species affected to determine if additional measures are necessary. The City of Santa Cruz would report the incident to the Office of Protected

Resources (OPR), NOAA Fisheries (PR.ITP.MonitoringReports@noaa.gov) and to the West Coast regional stranding network (866–767–6114) as soon as feasible. If the death or injury was clearly caused by the mailto:PR.ITP.MonitoringReports@noaa.gov mailto:PR.ITP.MonitoringReports@noaa.gov

11 MAY 2023

specified activity, the City of Santa Cruz must immediately cease the activities until NOAA Fisheries OPR is able to review the circumstances of the incident and determine what, if any, additional measures are appropriate to ensure compliance with the terms of the IHAs. The report would include the following information: a) time, date, and location (latitude/longitude) of the first discovery (and updated location information if known and applicable); b) species identification (if known) or description of the animal(s) involved; c) condition of the animal(s) (including carcass condition if the animal is dead); d) observed behaviors of the animal(s), if alive; e) if available, photographs or video footage of the animal(s); and f) general circumstances under which the animal was discovered. The City of Santa Cruz would not resume their activities until notified by NOAA Fisheries.

16. Post-Construction Replacement of Haul-out Areas. All known and potential haul-out sites that were removed from the work area prior to construction will be returned to their approximate location.

17. Post-Construction Monitoring. Post-construction monitoring will be conducted to determine if harbor seals resume their use of Dock F and FF as primary haul-out sites. NOAA Fisheries may require additional project conditions, to be applied depending on the outcome of post-construction monitoring.

The above-listed measures shall be implemented during all project-related construction activities.

3 Monitoring Methodology

Hydroacoustic and in-air monitoring will be conducted for a subset of the in-water pile driving activities, beginning with monitoring for the first in-water pile driven or for the first two full days of in-water pile driving, whichever is greater. The minimum number of piles that will be installed or removed for which hydroacoustic and in-air sound pressure level monitoring will need to be performed are shown in Table 3. In addition to the piles called out in Table

3, if the pile driving mechanism is changed (i.e., from vibratory to impact driven), monitoring will need to be performed for any pile type and driving type for which the threshold distances has not been established. Monitoring will need to be performed for the entirety of the pile driving session of each pile.

3.1 Contractor Requirements

The acoustical monitoring contractor shall possess a minimum of a bachelor’s degree in a related field2, with demonstratable experience in noise monitoring and analysis. The contractor will submit a detailed description of their qualifications, experience in in-air noise monitoring, hydroacoustic measurements and analysis.

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Table 3. Summary of Monitoring Requirement for Piles to be Installed or Removed

Location

Total

Number

Piles to

Monitor Pile Type

In Water

• Removal - Bridge Bridge Bent 6 4 1 14-inch P/C Concrete

• Remove Dock FF & TT Piles Dock FF & T 35 4 14-inch P/C Concrete

Total In Water Removal 39

• Install New Permanent Bridge

Piles

Bridge Bent 4 2 1 30-inch CIDH1

Bridge Bent 5 4 1 30-inch CISS

Bridge Bent 6 4 1 30-inch CISS

Bent 7 4 1 30-inch CISS

Bent 8 4 1 30-inch CISS

Bent 9 8 1 16-inch CISS

Bridge Subtotal 26

• Install New Dock FF & T Piles 35 4 14-inch P/C Concrete

Total In Water Bridge Pile

Installation

Optional In Water

• Install and Remove Trestle:

Install Temporary Piles Adjacent to Bridge 120 10 12-inch steel pipe piles

Remove Temporary Piles Adjacent to Bridge 120 10 12-inch steel pipe piles

Total Optional In-Water Pile

Installation

Note:

1 Permanent casing will be driven or vibrated into place.

2 To support a relocation of a sewer line that is under consideration.

3.2 Sound Monitoring Equipment and Monitoring

Requirements

The contractors shall provide a list of proposed sound level monitoring equipment, along with specifications and a description of the purpose. The measurement range in terms of amplitude (in dB referenced to one micropascal

(re: 1 µPa) for hydroacoustic measurements and referenced to 20 micropascals (re: 20 µPa)) for in-air measurements), sensitivity and frequency range for each transducer and piece of equipment shall be stated. A minimum frequency range of 20 Hz to 20 kHz and a minimum sampling rate of 44,100 Hz will be used when monitoring. Sampling rates higher than 48 kHz are preferred. Table 4 describes the minimum requirements of the equipment to be used. In addition to the equipment selection, quality control/quality assurance procedures should be described (e.g., how will system responses be verified and how will data be managed).

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To facilitate further analysis of data full bandwidth, time-series underwater signals shall be recorded as a wave file

(.wav) or similar format. Data compression algorithms or technologies (e.g. MP3, compressed .wav, etc.) will not be applied to the recordings.

Table 4. Example Equipment for Underwater and In-Air Sound Monitoring

Item Specifications

Minimum

Quantity Usage

Hydrophone

Receiving Sensitivity =

-211 dB ± 3dB re. 1Vrms/µPa

OR

-203 dB ± 3dB re. 1Vrms/µPa

Capture underwater sound pressure levels and convert to voltages that can be recorded/analyzed by other equipment.

Signal Conditioning

Amplifier

Amplifier Gain-

0.1 mV/pC to 10 V/pC

Transducer Sensitivity Range-

10-12 to 103 C/MU

Adjust signals from hydrophone to levels compatible with recording equipment.

Calibrator

(pistonphone-type) with Hydrophone

Coupler/Adaptor

Accuracy-

IEC 942 (1988) Class 1

Calibration check of hydrophone in the field.

Digital Signal

Analyzer

Sampling Rate-

48kHz or greater

Analyzes and transfers digital data to laptop hard drive.

Laptop computer

OR

Digital Audio

Recorder

Compatible with digital signal analyzer

Record digital data on hard drive or digital tape.2

If water velocity ~>

1m/s, Flow shield

Open cell foam cover or functional equivalent 2 Eliminate flow noise contamination.

Microphone (free field type)

Range- 30 – 120 dBA

Sensitivity-

-29 dB ± 3 dB (0 dB = 1 V/Pa)

Wind Screen

Monitoring airborne sounds from pile driving activities.

Sound Level Meter

IEC 61672-1:2013, ANSI S1.4-

2014 Class 1

Monitoring airborne sounds from pile driving activities.

Real Time and Post-analysis software

Monitor real-time signal and post-analysis of sound signals.

Note:

1 All measurement systems shall have current National Institute of Standards and Technology (NIST) traceable calibration.

Prior to monitoring, a standard depth sounder or a weighted line will record depth before pile driving commences.

The hydrophone will be attached to a nylon cord or a steel chain if the current is swift enough to cause strumming of the line. The nylon cord or chain will be attached to an anchor that will keep the line at a set distance from the pile. The nylon cord or chain will be attached to a float or tied to a static line at the surface 10 meters from the pile.

The distance will be measured by a tape measure, where possible, or a rangefinder. To the extent practicable there will be a direct line of acoustic transmission (direct line-of-sight) through the water column between the pile and the hydrophones.

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The onsite inspector/contractor will inform the acoustics specialist when pile driving is about to start to ensure that the monitoring equipment is operational. Underwater sound levels will be continuously monitored during the entire duration of each pile being driven with a minimum one- third octave band frequency resolution. The wideband instantaneous Peak, SEL, and RMS values of each pile should be monitored in real time during construction to ensure that the Project does not exceed its authorized take level. Peak and RMS pressures will be reported in dB re:1 µPa, and SEL will be reported in dB re: 1 µPa2·s.

Prior to, and during, the pile driving activity, environmental data will be gathered, such as water depth and tidal level, wave height, wind direction and speed and other factors that could contribute to influencing the underwater and in-air sound levels (e.g. aircraft, boats, etc.). The start and stop time of each pile driving event will be recorded and the time at which the bubble curtain or functional equivalent5 is turned on and off will be logged.

The contractor or agency will provide the following information, in writing, to the acoustical specialist conducting the hydroacoustic and in-air monitoring for inclusion in the final monitoring report: a description of the substrate composition, approximate depth of significant substrate layers, hammer model and size, hammer energy settings and any changes to those settings during the piles being monitored, depth pile driven, blows per foot for the piles monitored, and total number of strikes to drive each pile that is monitored.

3.3 Pile Driving Measurements for Fish and Marine

Mammal Consultations

For underwater measurements, hydrophones will be positioned as outlined below:

• Near Position. A stationary hydrophone will be positioned at a distance of 10 meters from the piles being driven to observe the measurements in real-time. If the water depth at 10 meters is not at least 1.5 meters

(5 feet), the closest distance to 10 meters will be used that has a minimum water depth of 1.5 meters. The hydrophone should be placed at approximately mid-depth.

• Middle Position. A second stationary hydrophone recording system will be positioned at approximately 20 to 50 meters from the pile being driven, at a measurement location at a distance equal to three times the water depth at the pile being driven, at a depth of 0.7 to 0.85 times the depth from the surface and at 1 meter above the bottom. This measurement location will be used to measure the extent of fish cSEL thresholds and marine mammal thresholds, and to calculate the site-specific transmission loss. This position will be a continuous recording of the pile being driven and the data will be further analyzed after monitoring completion.

• Distant Position. A third stationary hydrophone recording system will be positioned at approximately 410 meters from the pile being driven to measure the extent of marine mammal thresholds and to calculate the site-specific transmission loss. This position is necessary for the impact driving of 36-inch steel pipe piles, 30-inch steel pipe piles, and wide flange beam piles, and is not necessary for the impact driving of concrete piles.

5 A functional equivalent must function as well as or better than the attenuation device that was proposed during consultation or required by the ESA consultation or applicable permits. It must achieve the same or better sound level reductions that were used in the calculations during ESA consultation or the permitting process.

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For vibratory monitoring data will be analyzed by calculating 10-second RMS values for every 10 seconds for each pile. The 10-second RMS values will be linearly averaged for the entire pile and reported as the average RMS. The average RMS will be calculated for each marine mammal functional hearing group previously described.

For impact pile-driving, the Peak, impulse RMS, and SEL levels of each strike will be monitored in real time using sound-level meters (SLMs). The cSEL will be subsequently computed. The impact pile driving pulse RMS levels will be subsequently measured from recordings.

3.4 Background Underwater Sound Levels

Background underwater sound levels will be measured for a minimum of three full 24-hour cycles (i.e., 6 am to 6

am) in the absence of construction activities to determine background sound levels (NMFS, 2012a). Analysis will be conducted using both data from the full range of frequencies recorded (typically 20 Hz to 20 kHz) and using high pass filters at 7 Hz, 75 Hz, and 150 Hz thus eliminating those frequencies below these levels (NMFS, 2012a) which follows the marine mammal functional hearing groups.

Background underwater sound level data should be collected during the season when pile driving will occur. If pile driving is anticipated to occur in more than one season, then data should be collected to capture seasonal variability. If it is not possible to collect data in more than one season, winter season is preferable since sound levels in the winter are likely lower (i.e., less recreational boat traffic). The location of background sound measurements needs to be in close proximity to the area of the proposed activity. One hydrophone is sufficient for conducting measurements. The hydrophone should be placed within approximately 500-meters of the proposed activity. Hydrophone depth should be between mid-water column.

Data will be used to calculate 30-second Root Mean Square (RMS) values for each 30 seconds of the three 24-hour cycles measured. These data will be used to calculate and plot a Cumulative Distribution Function (CDF)

(NMFS, 2012a). Overall background sound levels will be reported as the 50% CDF and include a spectral analysis of the frequencies (NMFS, 2012a) for a minimum of one hourly cycle. Alternately, if pile driving will be conducted during the daytime only the background sound levels collected during daytime hours (6am to 6pm) can be used in this analysis.

Short-term background underwater…