B09_amd_5_attach_23_2021_08_18___Supplemental_Information_Repairs_and_Seismic_Upgrades_to_Alcatraz_Wharf_0005.pdf

Stabilize 1939 Alcatraz Wharf Supplemental Information Produced for the National Park Service August 18, 2021

Produced by Moffatt & Nichol 2185 North California Blvd. Suite 500 Walnut Creek, CA, 94596

(925) 944-5411| www.moffattnichol.com http://www.moffattnichol.com/

Stabilize 1939 Alcatraz Wharf Project

August 18, 2021 i

TABLE OF CONTENTS

LIST OF ACRONYMS .......................................................................................................................................................... ii

1. Introduction

1.1. Background/History

1.2. Site and Project Background

1.2.1. Project Details

1.3. Minimization Measures

2. Listed Species and Critical Habitat in the Project Area

2.1. Habitats of Particular Concern (HAPC)

3. Effects of the Action

3.1. Direct Impacts

3.2. Indirect Impacts

3.3. Species Specific Impacts

3.4. Cumulative Effects

4. Literature Cited

LIST OF FIGURES

Figure 1. Project Location Figure 2. Alcatraz Fixed Wharf and Finger Pier Figure 3. Isometric View of Wharf Structure Figure 4. Finger Pier Figure 5. Moveable Landing Structure Figure 6. Piles in Intertidal with Substantial Section Loss Figure 7. Damage to beams observed June 6, 2020 Figure 8. Finger Pier Figure 9. Finger Pier Landing Figure 10. Missing Piles at the Finer Pier Landing Figure 11. Substrate Underneath the Wharf

LIST OF TABLES

Table 1. 2019 Pile Condition (M&N 2019) Table 2. 2019 Beam Condition (M&N 2019) Table 3. Project Elements Table 4. NMFS ESA Listed Species with Potential to Occur in the Project Area Table 6. Fill Quantities Below MHHW

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LIST OF ACRONYMS

ACZA Ammoniacal Copper Zinc Arsenate BCDC Bay Conservation and Development Commission BMP Best Management Practices CDFW California Department of Fish and Wildlife CH Critical Habitat CWA Clean Water Act DDT Dichlorodiphenyltrichloroethane EFH Essential Fish Habitat EPA Environmental Protection Agency ESA Endangered Species Act ESU Evolutionarily Significant Unit HAPC Habitat Area of Particular Concern HDPE High Density Polyethylene lf Linear Feet MLLW Mean Lower Low Water M&N Moffatt & Nichol MMPA Marine Mammal Protection Act MSA Magnuson Stevens Act NMFS National Marine Fisheries Service NOAA National Oceanic and Atmospheric Administration NPS National Park Service PCBs polychlorinated Biphenyls PPT Parts Per Thousand SAV Submerged Aquatic Vegetation sf Square Feet USFWS U.S. Fish and Wildlife Service

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1. INTRODUCTION

1.1. BACKGROUND/HISTORY

The purpose of this document is to provide supplemental information to regulatory permit applications for the Stabilize 1939 Alcatraz Wharf Project. The purpose of this Project is to perform necessary repairs to the fixed wharf and associated timber finger pier. The Project also proposed to bring the wharf into compliance with current seismic and safety code requirements. The Project involves:

• Repairs to the fixed wharf:

o Sleeving of up to 206, 16-inch steel shell concrete piles o Repair of approximately 3700 square feet (sf) of the existing slab o Repair of approximately 5000 sf of the existing beams o Replacement of up to 5, 16-inch diameter concrete piles with 16-inch diameter steel pipe piles o Installation of 10, new 30-inch steel seismic piles at the wharf

• Repairs to the associated timber finger pier:

o Replacement of up to 9, 12-14-inch -treated timber piles with 14-inch ammoniacal copper zinc arsenate (ACZA)-treated timber piles coated in polyurea.

o Replacement of up to 4, 12-14-inch diameter timber piles with 10.75 diameter steel pipe piles with high-density polyethylene (HDPE) sleeves o Installation of one additional 10.75-inch diameter steel pipe pile with an HDPE sleeve o Minor cross bracing and decking repair as necessary o Replacement of the timber and steel finger pier landing

The proposed Project is necessary to maintain public safety and ensure the structural integrity of the Wharf. There is no proposed expansion of the Wharf or increase in use of the Wharf under this Project.

National Park Service (NPS) initiated consultation with National Marine Fisheries Service (NMFS) in March of 2021 to address the proposed action in compliance with Section 7 of the Endangered Species Act (ESA). Section 7 assures that, through consultation (or conferencing for proposed species) with the Services; both US Fish and Wildlife Services (USFWS) and the National Oceanic and Atmospheric Administration’s (NOAA) Fisheries Service, also known as NMFS, federal actions do not jeopardize the continued existence of any threatened, endangered, or proposed species, or result in the destruction or adverse modification of critical habitat (CH). There are no USFWS ESA-listed species within the Project area that have potential to be impacted by the Project. The NMFS consultation will also address Essential Fish Habitat (EFH) under the Magnuson Stevens Act (MSA) and marine mammals protected under the Marine Mammal Protection Act

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(MMPA). National Marine Fisheries Service (NMFS) consultation will be forwarded to all applicable agencies once complete.

1.2. SITE AND PROJECT BACKGROUND

Site Background

Alcatraz Island is located in San Francisco Bay which receives tidal saltwater inputs from the Pacific Ocean (NPS 2017).

San Francisco Bay can be divided into three segments the North Bay, Central Bay, and South Bay. The Project is located in the Central Bay which consists of predominantly cold saline ocean water and low total suspended sediments. Water Quality within the Central Bay is primarily influenced by tidal inflow which dictates circulation, flushing, and water exchange. Common sources of pollution in the Bay include oil leaks, grease, construction materials, waste materials, landscaping runoff, and erosion of disturbed sediments. The Central Bay is listed as an impaired waterway. Clean Water Act (CWA) 303(d) Listed pollutants in Central Bay include: chlordane, dichlorodiphenyltrichloroethane (DDT), dieldrin, dioxin compounds, furan compounds, invasive species, mercury, polychlorinated biphenyls (PCBs), selenium, and trash.

Oxygen levels in the Bay are typically well oxygenated.

Alcatraz Island is an important nesting area for colonial waterbirds, however the dock area due to its frequent daily use by NPS and visitors is not a colonial bird management area. Waterbirds are common on Alcatraz island and nest from February 15 to early September. In addition, Canada goose (Branta canadensis), mallard (anas platyrbynchos), common merganser (Mergus merganser), Anna’s hummingbird (Calypte anna), common raven (Corvus corax), brown-headed cowbird (Molothrus ater), song sparrow (Melospiza melodia), white-crowned sparrow (Zonotrichia leucophrys) and house finch (Carpodacus mexicanus) have been known to breed on the island. The Alcatraz bird census has been conducted yearly since 1993 during the fall and winter months. Over eighty-nine species were identified from these surveys between September 1998 and January 1999. The five most common species were western gulls (larus occidentalis), white-crowned sparrow (zonotrichia albicollis), song sparrow (melospiza melodia), double-crested cormorant (phalacrocorax auratus), and common raven (Corvus corax).

Alcatraz Island consists of a steep rocky shoreline. The shoreline near the proposed repairs consists of rip rap and rock outcroppings. Before occupation by the Europeans, Alcatraz Island was sparsely vegetated and is now mainly consists of non-native vegetation. Most of the shoreline consists of steep cliffs that do not support vegetation, however some of the more gradually sloping cliffs support a variety of introduced plants. Some of the less steep cliffs provide habitat for succulents, agave, sourgass, sweet alyssum, wild radish and large shrubs. Substate under the Wharf consists of rock.

Subsurface conditions on Alcatraz Island consist of Franciscan Complex sandstone bedrock. The bedrock is shallow and typically found between one and two feet below the ground surface (Langan 2018).

The Stabilize 1939 Wharf Project (Project) is located on Alcatraz Island approximately one mile north of downtown San Francisco (Figure 1). Alcatraz Island is a former federal prison and military reservations. It became part of the Golden Gate Recreation Area in 1972 and is now a popular tourist destination. The area is zoned as a National Park and offers a variety of trails, exhibits, and programs for visitors.

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The fixed wharf (wharf) is located on the southeastern side of the Island (Figure 2). The finger pier and finger pier landing start on the north side of the concrete wharf and extend in the northwest direction out from the wharf (Figure 2). The wharf connects to a ferry float that provides the primary access to Alcatraz Island for both the public and Alcatraz Island staff.

Ferry tickets are available for purchase from Pier 33 on the San Francisco Embarcadero. Barges moor on the bay side of the Finger Pier and pump out waste generated on the island as well as pump in fresh water used on the island. The landside of the finger pier as well as the landing has limited use for the berthing and passenger unloading for small vessels.

The first wharf at Alcatraz was built in 1852 when Alcatraz Island was used as a fort to guard the entrance to San Francisco Bay. The first wharf was made of timber, but was replaced with a concrete dock in 1934. Previous repair episodes have been undertaken, including general maintenance and expansion of the Wharf. The current wharf is composed of a reinforced concrete deck and beams which are supported by steel shell concrete piles. The existing concrete wharf is approximately 24,500 square feet and is supported by 252, 16-inch diameter piles (Figure 3). The beams span between piles and are nominally spaced at ten foot on center each way. The typical slab thickness is 8 inches and the typical beams are 24 inches wide and 15 inches deep. For spans over 12 feet long, the beam depth increases to 24 inches. The majority of the piles are reinforced concrete within a steel casing. A small number of the piles replaced during the 1991 partial retrofit are solid concrete and do not have steel jackets.

Inspection of the wharf’s structural condition was performed in 1988 and 1998 which led to the structural repairs and seismic upgrades performed in 2001. The work in 2001 was cut short and therefore not all of the repairs and seismic upgrades were completed. At some beam locations where the repairs were marked as omitted, it appears that some demolition work was completed , but the subsequent beam repair was not, leaving reinforcing exposed to the marine environment. These beams have significantly reduced structural capacity. The wharf deck is concrete and supports a restroom, bookstore, guard tower, and ranger station (Figure 2 and 3).

The earliest photos of the original finger pier are dated to 1940. In 1998, the entire finger pier was demolished and rebuilt in near original configuration, with the addition of fender piles and restoration of the historic dolphin piling configuration. The existing finger pier framing members are all timber with bolted and nailed connections (Figure 4). The walkway is also constructed of timber decking. The typical row (“bent”) is spaced ten feet apart and is composed of three timber bearing piles. On the land side there are timber fender piles and on the bay side there are HDPE covered steel fender pile. The fender piles frame into the pier via a timber bull rail. Cross bracing and batter piles exist on some bents to provide additional lateral stability.

The finger pier landing was originally built circa 1939 as a landing connected to a wooden float. The float was removed, the landing extended and the current pulley system installed. The existing landing is composed of a timber deck supported by steel channel sections with diagonal bracing (Figure 5). The landing is supported by the fixed wharf at its top end and hung from a hoisting system on the other end. To access the landing from the bay during different tide levels, a hoist system composed by a pulley system and motor is used to raise and lower the end of the landing. Fender piles extend along the length of the landing and onto the concrete wharf in the northwest direction.

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Figure 1. Project Location

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Figure 2. Alcatraz Fixed Wharf and Finger Pier

Figure 3. Isometric View of Wharf Structure

Ferry Float

Restroom

Building #64

Finger Pier Movable Landing

Project Boundary

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Figure 4. Finger Pier

Figure 5. Moveable Landing Structure

Project Background

The wharf has deteriorated in the saltwater environment for the past 78 years. Severe deterioration in some locations was identified in the Alcatraz Fixed Wharf Condition Assessment Report (2017 Condition Assessment) completed by M&N and dated November 8, 2017. The 2017 Condition Assessment found that the overall condition of the supporting substructure

Landing

Lift System

Fixed Wharf

August 18, 2021 7 foundation was fair to poor. The main areas of deterioration were the steel pipe piles (Figure 6) and concrete beams/slab on the underside of the deck (Figure 7), particularly along the shore and on the north side of the wharf (Figure 6). The outer steel pile shell is completely oxidized (rusted) in the upper 10 ft, from about -1 ft mean lower low water (MLLW) to the top at the bottom of the Wharf slab. Many of the piles along the shore side of the wharf have significant section loss within the intertidal zone (Figure 6). This is likely due to abrasion from the loose rocks that are moved by wave action.

In 2018 M&N completed a basis of design report for the Wharf which developed a repair design for the deteriorated concrete structure (beams, slabs, and piles) with the goal of restoring the structural capacity and enabling the wharf to safely support the gravity and current operation loads. During preliminary analyses it was also found that the wharf’s lateral load resisting system is deficient when utilizing the demands from the current applicable seismic and safety code requirements.

In 2019 M&N completed additional onsite observations of the wharf. The field work, performed over several days, included a visual inspection of accessible structural members. Pile conditions were categorized as follows:

• Type 1: Original pile with an obstructed view or no concrete cracking

• Type 2: Original pile with visible concrete or reinforcement (rebar) damage

• Type 3: Pile completely missing

• Type 4: 2000 Retrofit pile

• Type 5: Pile covered with 2000 era steel jacket

Damage to beams and slabs was also identified and categorized as either no observed damage, Type 1: concrete repair only, or Type 2: rebar and concrete repairs. Table 1 and 2 summarize the results from this condition assessment.

Table 1. 2019 Pile Condition (M&N 2019) Pile Condition # of Piles Repair Lengths (lf) Type 1: Original Pile with Obstructed View, No Concrete Cracking 138 1818 Type 2: Original Pile with Visible Concrete or Rebar Damage 71 779

Type 3: Pile Completely Missing 3 38

Type 4: 2000 Retrofit Pile 34 0

Type 5: 2000 Steel Jacket 6 0

Table 2. 2019 Beam Condition (M&N 2019) Structural Member

Repair Type Type 1: Concrete Repairs Only Type 2: Rebar and Concrete Repairs

Length (lf) Area (sq ft) Length (lf) Area (sq ft) Beam 548 1096 2032 4064 Slab - 1307 - 2412

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Figure 6. Piles in Intertidal with Substantial Section Loss

Figure 7. Damage to beams observed June 6, 2020

M&N engineers completed a condition assessment of the finger pier and landing on April 9, 2019 (M&N 2019). The finger pier and landing were in fair condition. Four piles were missing from the finger pier and several exhibited section loss (Figure 8). In addition, almost all of the cross bracings exhibited some level of deterioration and some were missing (Figure 8). The decking and stringers at the finger pier were in good condition. The landing structure (Figure 9) was not in

Damage to beam

Section loss

August 18, 2021 9 repairable condition and it was noted that the structure should be replaced in its entirety. There were three piles missing from the landing structure (Figure 10) and the cross bracings had deteriorated at the ends such that they no longer provide stiffening to the structure. The 2019 condition assessment determined that the landing should have limited use and no public access.

Figure 8. Finger Pier

Figure 9. Finger Pier Landing

Missing pile

Missing cross bracing

Landing

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Figure 10. Missing Piles at the Finer Pier Landing

1.2.1. PROJECT DETAILS

The Project proposes necessary repairs to the existing wharf structure and associated finger pier and landing. The project also proposes seismic upgrades to bring the wharf into compliance with current seismic and safety code requirements. The repairs and seismic upgrades proposed as part of this Project are reflective of the damage identified in the 2017 Wharf Condition Assessment (M&N 2017), 2018 Basis of Design Report (M&N 2018), Timber Dock Condition Assessment (M&N 2019), and 2020 field investigations. The proposed Project elements are summarized in Table 3 and described within the text below.

Table 3. Project Elements Location Element

Fixed Wharf Repair 206, 16-inch diameter piles pre-cast concrete piles with fiberglass jackets Install up to two new 16-inch diameter steel pipe piles to support the seismic joint Replace up to three 16-inch diameter concrete piles will steel pipe piles to support the seismic joint Install ten new, 30-inch diameter steel pipe piles Repair approximately 3,700 sf of existing the concrete slab Repair approximately 5000 sf of existing concrete beams

Finger Pier Replace nine, 12-14-inch diameter treated timber piles with 12-14-inch diameter ACZA-treated timber piles with polyurea coating.

Replace approximately three ACZA-treated cross braces with ACZA-treated polyurea coated braces.

Missing pile

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Location Element

Finger Pier Minor in kind ACZA-treated decking repairs as needed Finger Pier Landing Replace up to nine, 12-14-inch diameter ACZA-treated timber piles with 12-14-inch diameter ACZA piles with polyurea coating.

Replace up to four 12-14-inch diameter ACZA-treated timber piles with 10.75 inch steel piles with HDPE sleeves Install up to one new 10.75-inch diameter steel pipe pile with an HDPE sleeve Replace steel framed timber decked landing in kind

Fixed Wharf

Pile repairs

Approximately 206 of the existing piles are in need of repairs (Table 1). M&N engineers determined that repairs could be completed by sleeving the existing piles as opposed to fully replacing the piles. Therefore, pile removal or driving is not proposed for this Project element. Pile sleeving will not require cutting through the existing concrete deck and is anticipated to be generally less environmentally impactful than pile replacement. Pile repairs could occur for ten months.

The Project proposes to remove existing damaged steel jacket shells with a flame cutter. The existing damaged section of the steel shell jackets would be removed to a location where the remaining section of the jacket is at least ¼” thick. Some jackets may be removed above the waterline while others will need to be removed well below the waterline. Upon removal of the steel shell jackets, if spalling of the concrete pile underneath the jacket is observed, a jackhammer will be used to remove the damaged concrete. Jackhammering could occur above water and in-water. Underwater jackhammering would be avoided, but may be necessary in some cases. The jacket would continue to be removed to at least 6” below the extent of any major concrete damage. Damaged rebar will also need to be replaced. Rebar with greater than 80% damage will be cut out and new rebar will be clamped onto the existing undamaged rebar. Rebar will be cut using an oxyacetylene torch or angle grinder and a handheld impact driver will be used to install the bar splice. A fiberglass jacket would then be installed around the pile, covering the length of the pile from beam soffit to the top of competent rock, to 1 foot below mudline or to an elevation of -4 ft MLLW whichever occurs first. Substrate would be shoveled away from the piling at the mudline and then replaced once the jacket is secured. A multi-purpose marine grade epoxy grout would then be used to fill the void space inside the jacket to complete the repair. Fiberglass jacketing work would be completed by hand, using divers accessing the work area by boat.

Upon removal of all damaged concrete and replacement of the damaged rebar a multipurpose marine epoxy grout filled fiberglass jacket would be installed around the damaged piles. Fiberglass jackets would be approximately 20-inches in diameter and would be wrapped around the existing pile. Pile jackets would extend from the beam soffit to -4 feet MLLW or to 1’ below mudline or to the top of competent rock, whichever occurs first. A diver could use a handheld shovel to move the substrate around so that the sleeve can be placed approximately 1 foot deep into the substrate if needed. Substrate would then be moved back into place by shovel or hand. The fiberglass sleeves would then be filled with a multipurpose marine epoxy grout. Fiberglass sleeve installations are anticipated to be completed with hand tools by a diver and by boat

August 18, 2021 12 in deeper waters and by crew members on land in areas where the tide recedes sufficiently for crew member to walk or wade. This operation can be performed with minimal noise disturbance.

Three, 16-inch diameter piles are missing. Up to two additional 16-inch diameter piles will be installed to support the deck at the planned seismic joint. Therefore, up to 5, 16-inch diameter piles steel pipe piles will be installed. Installation of the 5, 16-inch diameter piles would occur in shallow water conditions less than 7.5 ft mean lower low water (MLLW).

Replacement piles may be placed into the existing drilled sockets and grouted in place or if the existing sockets are not deep enough it may be necessary to drill new sockets for the piles. New sockets will be required for at least the two new piles at the seismic joint. To drill a new socket, a casing (to prevent spoils from entering the bay) is first driven two to five feet deep into the silt/sediment layer until bedrock is reached. The installation of the casings would occur using an impact or vibratory hammer operated from the Wharf deck. If a vibratory hammer is used to install the casing through the overburden, an impact hammer would likely need to be used to set the casing into the bedrock to create a seal. The casing would likely be up to 30-inches in diameter and would be removed with a vibratory hammer once the pile is placed and grouted. A bubble curtain would be installed during impact pile driving of the casing and up to two casings could be installed per day with impact pile driving occurring for 20 to 30 minutes per casing. Rock sockets are then drilled to depth and pipe piles are grouted in. A rotary drill rig would be used to drill the rock sockets and would likely be approximately 24-inches in diameter. For these 16-inch diameter piles, drilling could occur for up to one hour per pile with up to two piles being installed per day. After the pipe pile is placed and grouted in the casing is removed.

A 2-foot by 2-foot pilaster is also proposed to be installed against the existing seawall to support the seismic joint. This pilaster is to be installed at a location where bedrock protrudes from the sea floor at an elevation higher than Mean Higher High Water (MHHW). A 2-foot by 2-foot by 2-foot deep socket will need to be cut into the rock mass for the pilaster installation. The socket will be cut with the aid of jackhammers and hand tools. All work for this retrofit item will happen in the dry.

Beam and Slab Repairs

Up to approximately 5,000 square feet of the existing beams have major to severe damage and approximately 3,700 sf of damaged slab requires repairs (Table 2). All slab and beam work will occur above water. A jackhammer will be used to remove the damaged concrete, and rebar with greater than 80% section loss will be cleaned/removed and supplemental rebar will be added. Rebar that is to be removed will be cut with the aid of a cutoff wheel or oxyacetylene torch.

Supplemental rebar will be added with the use of couplers and installed with the use of pneumatic impact wrenches. A jackhammer may be used during the entirety of the day and multiple hammers may be used at once. Following removal of the damaged concrete and replacement of the damaged rebar, the concrete section will be repaired.

There are two options for repairing the beam and slab concrete. One option would involve the construction and installation of form work followed by a concrete casting and the other would use shotcrete. If shotcrete is used, scaffolding and suitable sheeting shall be installed under all areas where shotcrete is being placed. The sheeting shall extend out far enough to capture all reasonable concrete rebound or overspray and prevent concrete from entering the water. Shotcrete may be preferable due to a lower cost of placement.

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Seismic Upgrades

The current structural capacity of the Wharf is not current with applicable seismic and safety code requirements. The proposed seismic upgrades will increase the structural capacity of the wharf to levels that are within current, applicable, seismic and safety code requirements. Seismic upgrades may occur concurrently with repairs. The Project proposes to install up to ten new 30-inch steel seismic upgrade piles. Installation of the 10, 30-inch diameter piles would occur in shallow water conditions less than 7.5 ft MLLW. Pile driving is not proposed for this Project element. Instead, a rock socket will be drilled with an auger drill, and the piles will be placed and grouted into the drilled holes. The auger drill will likely be approximately 42-inches in diameter.

To drill a rock socket, a casing is first driven using an impact hammer two to five feet deep into the silt/sediment layer until bedrock is reached. The casing will likely be approximately 48-inches in diameter and will prevent spoils from entering the bay. All debris would be cleaned from the shaft and disposed of at an appropriate upland facility. Up to one casings could be installed per day and casing driving could occur for 20 to 30 minutes per casing. The installation of the casings would occur using an impact or vibratory hammer operated from the Wharf deck. If a vibratory hammer is used to install the casing through the overburden, an impact hammer would likely need to be used to set the casing into the bedrock to create a seal. A bubble curtain would be used during impact pile driving of the casings. The casing is first driven through the overburden layer to bedrock (approximately two to five feet below the top of the silt/sediment layer) and then approximately 6-inches into the bedrock. Rock sockets are then drilled approximately 15 feet into the bedrock and the new steel pipe piles would be placed into the newly augured holes with a crane. The void annulus between the pile and rock would be filled with quick setting grout. Drilling of piles would occur from the top of the wharf deck and could occur for up to 5 hours per pile with two piles being installed per day.

To access the area beneath the wharf from the wharf deck for the drilling of the rock sockets, up to a 10 by 10-foot section of the wharf slab will need to be removed. A diamond saw, cable saw and jackhammers would be used to cut through the concrete wharf slab. Cutting of the wharf slab could take two hours per section with approximately two sections being cut per day. After the pile is installed the area of the wharf deck that was removed will be occupied by a seismic dolphin cap.

Finger Pier Repairs

At the finger pier landing there are approximately 13, 12-14-inch diameter -treated timber piles that are either missing or exhibiting section loss that need to be replaced. In addition, 1, 10.75-inch diameter steel pipe pile with an HDPE sleeve needs to be added to the landing to accommodate berthing capabilities.

Up to nine piles would be replaced in-kind at the finger pier to protect the historical integrity of the structure. Any replaced ACZA-treated piles would be coated in polyurea to prevent the leaching of ACZA into the marine environment. ACZA-treated cross bracings would also be replaced in kind with ACZA-treated cross bracings. The missing and deteriorated ACZA-treated timber piles at the landing would not be replaced in-kind and would instead be replaced with steel pipe piles with HDPE sleeves to accommodate safe berthing facilities. These piles are only visible from the water looking landward and therefore it has been determined that replacing timber piles with steel pipe piles with HDPE sleeves would not impact the historic integrity of the structure. Up to four, 12-14-inch diameter ACZA-treated piles could be replaced with 10.75-inch

August 18, 2021 14 diameter steel piles with HDPE sleeved. In addition, one new 10.75-inch steel pipe pile with an HDPE sleeve would be installed to the landing to accommodate berthing capabilities.

Existing damaged piles would be removed using a vibratory hammer where possible. Stubs broken off below the mudline would be left in place. Piles will be replaced using an impact hammer from a barge or top of deck. It is anticipated that there would be up to 250 blows per pile and that up to 8 piles could be installed per day. Impact pile driving could occur for approximately 20 minutes per pile. Cross bracing replacement would be done using pneumatic or electric hand tools. An ancillary quantity of decking and deck substructure replacement may be required to facilitate the pile replacements. All repairs to deck elements would be conducted from the deck surface (out of the water) utilizing electric hand tools.

The existing dilapidated steel framed, wood decked landing would be removed in its entirety and replaced with a prefabricated steel framed, wood decked landing. The existing landing would be detached from the wharf using pneumatic hand tools and/or torch cutting equipment and removed from the site using a crane and disposed of at an upland disposal site. The new prefabricated steel landing with timber decking would be brought in by barge and lifted into place using a crane. The new prefabricated landing would be connected to the wharf using pneumatic hand tools. Field welding may be required to adapt the lifting system of the existing lifting system to the new landing.

Duration

Total Project duration is anticipated to take up to 36 months including mobilization, down time, and demobilization. Work will be completed in sections to maintain public access to Alcatraz Island and the wharf throughout construction. Work would be completed in compliance with the waterbird nesting season restrictions stipulated within the 2001 Alcatraz Island Historic Preservation and Safety Construction Program Environmental Impact Statement (NPS 2001). In-water would occur during the in-water work window (anticipated to be June 1 through November 30). Day and nighttime work is proposed for the above water repairs subject to the restrictions outlines in Section 1.3. In-water work would be restricted to daylight hours.

Construction Equipment List

• Cranes

• Drill (likely a rock socket with drilled shaft caisson)

• Impact pile driver

• Pneumatic tools (such as chipping, demolition hammers and impact drivers)

• Jackhammer

• Oxyacetylene torch or angle grinder

• Diamond or wire saw

• Hand tools (such as hammers, concrete trowels, etc.)

• Scaffolding under wharf

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• Small boats

• A barge mounted crane

• A diver or dive team (as needed)

• Floating barge for staging (use of a barge is not anticipated but may be preferred by the selected contractor)

• Telehandler and forklifts for transportation of construction equipment and materials

1.3. MINIMIZATION MEASURES

The Project only proposes to repair existing piles and perform necessary seismic upgrades. The following construction Best Management Practices (BMPs) are also proposed to assure that potential environmental impacts are reduced:

Below are BMPs we have included for other similar projects. Please let me know if you foresee issues with these or if there are additional BMPs we will be proposing.

General measures

• Prior to implementation of each construction project, restricted areas would be identified and mapped by National Park Service staff. These areas would be delineated with input from resource specialists, interpretive, and maintenance/project management staff to ensure resource protection as well as adequate access for construction and Island operations. The areas would be clearly marked with temporary fencing or other signage prior to the arrival of materials and equipment, and would be enforced (as a contractual requirement) by the construction crew with monitoring by National Park Service staff.

• All construction workers would be provided with information on the biological resources of the Island, and the required mitigation measures. In addition, all construction workers would be required to attend an orientation on the sensitivity of the Island's natural resources and the requirements and mitigations to be implemented for resource protection. Attendance will also be required at periodic natural resource briefings throughout the breeding season. The required mitigation measures would be included in the construction contract documents and would be a binding requirement, and enforcement would be monitored by National Park Service staff through regular inspections by a qualified biologist and contract inspector.

• Construction of a false bottom beneath the Wharf deck to act as a debris catch, reducing the potential for materials to enter the water.

• If shotcrete is used the area under the shotcrete will be scaffolded and plywood will be installed to catch any rebound or overspray that may occur.

• All removed construction debris, including material removed from the drill shaft, will be collected, transported and disposed of at an appropriate offsite upland facility.

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• No debris, rubbish, concrete, or washings thereof, or other construction-related materials or wastes, oil, or petroleum products shall be allowed to enter into or placed where it would be subject to erosion by rain, wind, or waves and enter into jurisdictional waters.

• The applicant shall locate all construction materials away from the Wharf edge. Materials that are not being actively used shall be packed away in a storage location.

• A spill plan will be developed and appropriate spill control and clean-up materials (e.g., oil absorbent pads) shall be retained on site in case a fuel spill occurs. All construction vehicles and equipment shall be inspected before they are moved to the Project site, and shall not be moved to the site if leaking fluids that could result in spills of toxic materials. All construction vehicles and equipment used on site shall be well maintained and checked daily for fuel, oil, and hydraulic fluid leaks or other problems that could result in spills of toxic materials.

• Vehicle staging, cleaning, maintenance, refueling, and fuel storage shall take place in a vehicle staging area (on the contractors barge or to the southeast of the wharf). The fueling area will be double lined. Daily monitoring will occur to ensure there are no leaks. Oil absorbing pads, drip pans, or similar devices will be placed beneath the equipment when staged overnight to catch any leakage.

• Work barges will not be allowed to ground out. Additionally, work barges will not be positioned over submerged aquatic vegetation (SAV) for more than 24 hours.

Noise

• All construction vehicles or equipment, fixed or mobile, would be equipped with properly operating and maintained mufflers and acoustical shields or shrouds, in accordance with manufacturers’ recommendations.

• Prior to commencing construction, acoustic barriers would be constructed along the perimeter of construction sites. Wooden barriers (or treatments of equivalent effect) would be constructed at a height of approximately 8 feet for shielding ground-level activities and loaded vinyl curtains (or treatments of equivalent effect) would be draped to enclose elevated scaffolding.

• To the degree feasible, stationary noise-generating construction equipment would be centrally located on the project site or within equipment staging areas at the greatest distance possible from exterior areas.

• Loud mechanical equipment will be brought online slowly (employ a “soft-start”)

• A wood cushion block would be used during impact pile driving.

• Alternate hammer types to reduce underwater sound pressure would be used first (e.g., vibratory hammers) before using impact hammers where possible to minimize impacts to wildlife.

• If an impact hammer is used for casing installation a bubble curtains shall be used to minimize sound impacts.

• Pile-driving shall commence with a soft start procedure (ramping up) to alert nearby wildlife, allowing them to move out of the area prior to construction activities. For impact pile driving, contractors shall be required to

August 18, 2021 17 provide an initial set of strikes from the hammer at reduced percent energy, each strike followed by no less than a 30-second waiting period. This procedure shall be conducted a total of two times before impact pile driving begins. Where a vibratory hammer is used, contractors shall initiate sound from vibratory hammers for 15 seconds at reduced energy followed by a 1-minute waiting period. This procedure shall be repeated two additional times before full energy may be achieved.

• A maximum of one pile casing would be installed per day. No more than 200 blows a day would occur during casing installation.

• Seismic upgrade piles will be drilled into place as opposed to driven.

In-water Work

• In-water work shall be restricted to the environmental work windows protective of aquatic species (June 1- November 30).

• A biological monitor would survey the area for spawning herring during the spawning season from December through March. In-water activities may be restricted during this time if spawning herring are identified by the biological monitor.

• Fiberglass jackets will be filled with marine grade grout. Fiberglass jackets shall be installed, sealed, and extend above high tide to allow grout placement to minimize the risk of grout contacting surface waters. The two ends of the jackets shall be sealed, and air will be vented with ports.

• During fiberglass jacket installation, the contractor shall have a diver in place to make sure that forced grout is not being released into the Bay.

• Installation and application of epoxy, resin, or cementitious grout/fill will be conducted when predicted weather and ocean conditions allow effective control and full containment and shall remain dry until cured, in order to prevent any leaching of uncured treatment materials into coastal waters. Jackets shall be installed during low tide to the extent feasible. Work shall cease during inclement weather (large waves or heavy rain)

• A casing would be installed during drilling to prevent spoils from entering the water.

Birds

• Prior to construction, restricted areas would be identified and mapped by NPS staff.

• Exclusionary netting will be installed underneath the Wharf deck and will run along the perimeter of the dock where rock substrate abuts the deck Netting will remain in place and be maintained for the duration of the project.

• Other nesting bird exclusionary measures will include filling crevices, cavities, and gaps within the deck and finger pier using a marine-grade epoxy or additional metal mesh netting to block entrances to potential nests.

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• Visual barriers will be installed along fencing adjacent to the work area prior to the start of nesting season (February 15th) to prevent visual intrusion into adjacent breeding areas. Placement and type of barrier to be approved by National Park Service biologist.

• A contracted biological monitor for the project who would oversee monitoring and maintain the exclusion installations during the project.

• If Project activities are proposed to occur during the waterbird nesting season (February 15th through September 15th), nesting bird surveys will be completed by the biological monitor assure that nesting birds are not being by the proposed activities.

• Construction of additional pigeon guillemot nest boxes placed in strategic locations outside of the work area by the biological monitor. This would aid in providing new nesting locations for birds displaced from their nesting sites under the deck and finger pier.

• Area #2 in the 2001 FEIS: No nighttime use.

• Area #3 in the 2001 FEIS: If nighttime use is proposed, lighting would be directed toward the work areas only and appropriately shielded. Lighting placement would be reviewed and approved by a National Park Service biologist and maintenance staff during initial staging operations.

• If work occurs northeast of Building 64 (area 3a in the 2001 EIS), nighttime work will not be allowed.

• Movement of equipment and materials to and from staging areas from February 15 through September 15 would be restricted to daylight hours to prevent moving lights from disturbing sensitive areas.

• Transportation of materials to the Island by helicopter would be prohibited during the waterbird breeding season from February 15 until the young have fledged (usually mid-September).

Marine Mammals

• All avoidance and minimization measures for protection of marine mammals identified through the consultation with the NMFS Long Beach Protected Resources Division will be abided by.

• A 500-meter marine mammal exclusion zone will be established during all pile driving activities.

2. LISTED SPECIES AND CRITICAL HABITAT IN THE PROJECT AREA

This Supplemental Information identifies potential ESA-listed species to occurrences in the Project area, however actual occurrences and impacts will be determined through Section 7 consultation with NMFS. National Marine Fisheries Service (NMFS) consultation will be forwarded to all applicable agencies once complete.

ESA-listed species identified in this Supplemental Information as having potential to occur in the Project area include;

green sturgeon (Acipenser medirostris), Central California coast Evolutionarily Significant Unit (ESU) steelhead (Oncorhynchus mykiss) California Central Valley ESU steelhead (Oncorhynchus mykiss), Central Valley spring-run chinook salmon (Oncorhynchus tshawytscha), Sacramento River winter-run chinook salmon (Oncorhynchus tshawytscha) and

August 18, 2021 19 humpback whales (Megaptera novaeangliae) (Table 4, NMFS 2021). Green sturgeon, Central California Coast steelhead, and Sacramento Winter-run Chinook critical habitat (CH) occurs in the Project area. There are no USFWS ESA-listed species with potential to occur in the Project area that have potential to be impacted by the Project (USFWS 2021).

Marine mammals protected under the Marine Mammal Protection Act (MMPA) may also occur in the project area. Marine mammal occurrences and potential impacts to marine mammal species will be determined through consultation with the NMFS Long Beach Protected Resources Division.

Table 4. NMFS ESA Listed Species with Potential to Occur in the Project Area Specie Scientific Name Status Critical Habitat Green Sturgeon-Southern DPS Acipenser medirostris Threatened Yes

Central California Coast Steelhead Oncorhynchus mykiss

Threatened Yes

California Central Valley Steelhead Oncorhynchus mykiss

Threatened No

Sacramento Winter-run Chinook Salmon Oncorhynchus tshawytscha

Endangered Yes

Central Valley Spring-run Chinook Salmon Oncorhynchus tshawytscha

Threatened No

Sources: http://www.westcoast.fisheries.noaa.gov/maps_data/endangered_species_act_critical_habitat.html https://www.fisheries.noaa.gov/region/west-coast#species

2.1. HABITATS OF PARTICULAR CONCERN (HAPC)

Habitats of Particular Concern (HAPC) are considered important to ecosystem function, rare, or sensitive to human activities. Habitats of Particular Concern (HAPC) are high priority areas for conservation, management and/or research.

Within the San Francisco Bay- Delta Region NMFS has identified two communities considered special aquatic sites:

eelgrass and native oyster beds.

Eelgrass

Eelgrass has been granted special management considerations by the California Department of Fish and Wildlife (CDFW), USFWS, NMFS, Environmental Protection Agency (EPA), and the Bay Conservation and Development Commission (BCDC) due to the array of biological services it provides. Eelgrass can provide nursery grounds for Bay-Delta fish, provide substrate for a variety of benthic organism, provide rearing habitat, provide foraging areas for waterfowl, provide spawning habitat, and help stabilize shorelines (Boyer and Wyllie-Echeverria 2010). Eelgrass typically occurs in shallow, soft-bottom habitats. Threats to eelgrass beds within the San Francisco Bay include contact with boat propellers and anchors, dredging, and construction of in-water facilities such as docks and breakwaters.

Eelgrass has not been mapped within the Project area, with the closest known mapped location being 1.8 miles away at Angel Island (CDFW 2015). The area underneath and adjacent to the Wharf is rocky and does not provide suitable habitat for eelgrass (Figure 11).

Native Oyster Beds

NMFS has identified Olympia oysters (Ostrea lurida) as HAPC in San Francisco Bay. Olympia oysters are native to Western North America and can provide physical habitat for juvenile fish, foraging fish, crustaceans, worms and birds (ESA http://www.westcoast.fisheries.noaa.gov/maps_data/endangered_species_act_critical_habitat.html https://www.fisheries.noaa.gov/region/west-coast#species

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2015). They have also been noted to enhance sediment stabilization and can improve water quality by reducing suspended sediments Olympia oysters occur in brackish waters with salinities greater than 22 parts per thousand (ppt). They tend to occur in areas with hard substrate and low siltation rates. Oysters can occur growing on manmade structures such as marina floats, rip rap shorelines, and pilings. Threats to Olympia oysters include limited suitable hard substrate habitat, poor water quality and predation from marina snails, birds, at rays, and crabs.

Several accounts indicate that Olympia oysters were at one point abundant within the Bay (Zabin et al. 2010). However, recent studies indicate that while Olympia oysters have been observed within San Francisco Bay from Carquines Strait to South Bay they are no longer as common, especially in the North Bay. Small numbers of oysters have recently been documented at various rocky intertidal, rocky subtidal, and manmade habitats in the Bay. One extensive study by UC Davis from 2006 to 2007 indicated that while oyster scars can be found at many locations in the Bay, most live oyster populations occur at the Richmond and San Mateo bridges. There are no known occurrences of Olympia oysters at Alcatraz Island, however habitat underneath the Wharf is rocky and could provide suitable hard substrate for Olympia oysters (Figure 11).

According to the San Francisco Bay Subtidal Habitat Goals Report Alcatraz Island appears to be good habitat for Olympia oysters (Zabin et al. 2010).

Figure 11. Substrate Underneath the Wharf

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3. EFFECTS OF THE ACTION

Potential direct and indirect impacts from the proposed activities are described below.

3.1. DIRECT IMPACTS

Direct impacts are generally defined as impacts that physically contact the species and have the potential to cause physical damage. Direct impacts are caused by the activity and occur at the same time and place. The Project has the potential to create the following direct adverse impacts:

• Noise: In-water and in-air noise has the potential to disturb species. Minimization measures and BMPs such as compliance with the established in-water work window for the area, use of a bubble curtain, use of a wood cushion block, use of a soft start technique, establishment of acoustic barriers, and installation of bird exclusionary devices would reduce the potential for noise impacts.

• Water quality: General water quality/turbidity impacts could occur: The majority of sediment disturbances would occur from pile removal, driving and casing driving. A casing would be installed during drilling to prevent spoils from entering the water. Water quality and turbidity impacts from sediment resuspension are anticipated to be minor and localized for the proposed activity. The Proposed minimization measures and BMPs such as the construction of a false bottom beneath the Wharf deck to catch debris and the use of a diver to ensure that forced grout is not being released into the Bay will minimize any potential for water quality impacts to be significant on aquatic species or habitat.

• Benthic disturbances and fill impacts: Benthic disturbance and fill impacts could occur during pile sleeving and pile installation. Fill impacts are summarized in Table 6.

Table 5. Fill Quantities Below MHHW

Location Element Additional Fill (sf)

Additional Fill (cy)

Fixed Wharf

Repair 206, 16-inch diameter piles concrete piles with fiberglass jackets

260 23

Replace 3, 16-inch diameter piles 0 0 Install 2 new, 16-inch diameter piles 6.3 4.1 Install 10 new, 30-inch diameter steel pipe piles 49.1 417

Finger Pier

Replace 9, 12-14-inch diameter ACZA-treated timber piles in kind 0 0

Finger Pier Landing

Replace up to 4, 10.75-inch diameter ACZA-treated timber piles with 10.75-inch diameter steel pipe piles with HDPE sleeves

0 0

Install 1 new, 10.75-inch diameter steel pipe pile with an HDPE sleeve 1.1 1.0

Total 316.5 (0.007 acres)

445.1

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3.2. INDIRECT IMPACTS

Indirect impacts are generally defined as ecosystem changes that could affect food web dynamics.