Amendment 02 -FINAL_SAPReport_USCGSV_23May2024 With APPENDICES.pdf

FINAL

SAMPLING AND ANALYSIS PLAN REPORT

SEDIMENT CHARACTERIZATION STUDY TO SUPPORT

EPISODIC MAINTENANCE DREDGING AT

COAST GUARD STATION VALLEJO

VALLEJO, CALIFORNIA

Submitted to:

San Francisco Bay

Dredged Material Management Office 1455 Market Street

San Francisco, California 94103

Submitted by:

United States Coast Guard

CEU Oakland 1301 Clay Street, Suite 700N

Oakland, California 94612

MAY 23, 2024

Contract 70Z05019DWEAISI09 Task Order 70Z08822FESDV0023

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FINAL

SAMPLING AND ANALYSIS PLAN REPORT

SEDIMENT CHARACTERIZATION STUDY TO SUPPORT

EPISODIC MAINTENANCE DREDGING AT

COAST GUARD STATION VALLEJO

VALLEJO, CALIFORNIA

MAY 23, 2024

Contract 0Z05019DWEAISI09 Task Order 70Z08822FESDV0023

REVIEW AND APPROVALS:

Prepared by: 23 May 2024 Kaylee Popovich

WSP USA Environment & Infrastructure Inc.

Project Scientist (805-550-8752)

Date

Approved by: 23 May 2024 Kimbrie Gobbi

WSP USA Environment & Infrastructure Inc.

Project Manager (443-852-4637)

Date

Concurred by:

23 May 2024

Erica Geasler-Bromley WSP USA Environment & Infrastructure Inc.

Program Manager (810-813-1901)

Date

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FINAL Sampling and Analysis Plan Report Sediment Characterization Study to Support Maintenance Dredging at Coast Guard Station Vallejo Vallejo, California May 2024

Page iii

TABLE OF CONTENTS

Page

ACRONYMS AND ABBREVIATIONS .......................................................................................vi

1.0 INTRODUCTION ......................................................................................................... 1-1

1.1 Project Summary ..............................................................................................1-1

1.1.1 Purpose and Objectives ........................................................................1-2

1.1.2 Proposed Dredging Volumes and Depths ..............................................1-9

1.1.3 Proposed and Alternative Placement Options ........................................1-9

1.1.4 Project Timeline and Correspondence with Agencies Regarding

SAP Report Approval ........................................................................... 1-10

1.2 Site Description ............................................................................................... 1-10

1.3 Scope of Work ................................................................................................ 1-11

2.0 SITE HISTORY ........................................................................................................... 2-1

2.1 Summary of Prior Sediment Characterization Results .......................................2-1

3.0 METHODS .................................................................................................................. 3-1

3.1 Dredging Design ...............................................................................................3-1

3.2 Sampling Design ...............................................................................................3-1

3.2.1 Sampling and Testing Objectives ...........................................................3-2

3.2.2 Sample Identification .............................................................................3-2

3.2.3 Core Sample Locations and Depth ........................................................3-2

3.2.4 Reference and Control Sediment Sample Collection .............................3-9

3.2.5 Composite Areas ...................................................................................3-9

3.2.6 Sampling Platform, Navigation, and Vertical Control ..............................3-9

3.2.7 Sampling Collection, Processing, and Shipping ................................... 3-10

3.2.8 Separating Layers and Sample Preparation ........................................ 3-11

3.3 Tier II Physical and Chemical Testing ............................................................. 3-13

3.3.1 Tier II Data Quality Assurance/Quality Control ..................................... 3-15

3.4 Tier III Toxicity Tests ....................................................................................... 3-15

3.4.1 Ammonia Reduction ............................................................................ 3-16

3.4.2 Toxicity Data Analysis .......................................................................... 3-16

3.5 Modified Elutriate Test .................................................................................... 3-17

3.6 Deviations from the Final Study Sampling and Analysis Plan .......................... 3-17

4.0 RESULTS ................................................................................................................... 4-1

4.1 Physical Analysis ..............................................................................................4-1

4.2 Chemical Analysis .............................................................................................4-1

4.2.1 Sediment Chemistry Results .................................................................4-2

4.2.2 Site Water and Elutriate Chemistry Results ...........................................4-4

4.3 Tier III Data Analysis and Interpretation .......................................................... 4-13

4.3.1 Suspended Particulate-Phase Results ................................................ 4-13

4.3.2 Modified Elutriate Test (Comparison to Cullinan Ranch) Results ......... 4-13

4.3.3 Standard Elutriate Test (Comparison to SF-09) Results ....................... 4-13

4.3.4 Prediction of Water Column Toxicity During Disposal at SF-09 ............ 4-14

4.3.5 Solid-Phase Results ............................................................................ 4-23

4.4 Quality Assurance Quality Control Review ...................................................... 4-25

5.0 CONCLUSIONS AND RECOMMENDATIONS ........................................................... 5-1

5.1 Conclusions ......................................................................................................5-1

5.1.1 Physical and Chemical Analysis ............................................................5-1

5.1.2 Toxicity Evaluations ...............................................................................5-2

5.2 Disposal Suitability Recommendation ...............................................................5-2

Maintenance Dredging at Coast Guard Station Vallejo Vallejo, California May 2024

TABLE OF CONTENTS (CONTINUED)

Page iv

6.0 AGENCY SUITABILITY DETERMINATION ................................................................ 6-1

7.0 REFERENCES ............................................................................................................ 7-1

LIST OF TABLES

Table 2-1. Dredging Site History ...........................................................................................2-1 Table 3-1. Station Vallejo Proposed Dredging Locations, Design Depths, and Volumes .......3-1 Table 3-2. Vibracore Collection Log ......................................................................................3-5 Table 3-3. Chemical Analyses of Sediment, Elutriate, and Site Water Samples for

Unconfined Aquatic Disposal ............................................................................. 3-14 Table 3-4. Toxicity Test Species .......................................................................................... 3-16 Table 4-1. Physical Testing Results – Grain Size ..................................................................4-1 Table 4-2a. Station Vallejo Composite Sediment Chemistry Results (Dry Weight) ..................4-5 Table 4-2b. Station Vallejo Composite Sediment Chemistry Results for Dioxins and Furans

(Dry Weight) ........................................................................................................4-9 Table 4-3. Station Vallejo Seawater and Elutriate Analytical Chemistry Results .................. 4-11 Table 4-4a. Test Results for the 48-hour Water-Column Test with Mytilus galloprovincialis ... 4-15 Table 4-4b. Test Results for the 96-Hour Water-Column Test with Americamysis bahia

(SET) ................................................................................................................. 4-17 Table 4-4c. Test Results for the 96-Hour Water-Column Test with Americamysis bahia

(MET) ................................................................................................................ 4-19 Table 4-4d. Summary of Toxicity Test Results – Suspended Particulate-Phase .................... 4-21 Table 4-5. STFATE Mixing Model Results for Determining Potential Toxicity for Placement of Dredged Material at SF-09 ............................................................................. 4-22 Table 4-6a. Test Results for the 10-Day Solid-Phase Test with Neanthes arenaceodentata .. 4-23 Table 4-6b. Test Results for the 10-Day Solid-Phase Test with Leptocheirus plumulosus ..... 4-24 Table 4-6c. Summary of Toxicity Test Results – Solid-Phase ................................................ 4-24

LIST OF FIGURES

Figure 1-1. Project Vicinity .....................................................................................................1-3 Figure 1-2. Project Location ...................................................................................................1-5 Figure 1-3. Proposed Disposal Sites ......................................................................................1-7 Figure 2-1. Station Vallejo Historical Sampling Locations .......................................................2-3 Figure 3-1. Actual Sediment Sampling Locations and Composite Areas – Station Vallejo ......3-3 Figure 3-2. SF-09 Reference Sediment Collection Site ..........................................................3-7

LIST OF APPENDICES

APPENDIX A AGENCY CORRESPONDENCE AND DESIGN PLANS

APPENDIX B VIBRACORE LOGS

APPENDIX C VIBRACORE PHOTOLOGS

APPENDIX D ANALYTICAL CHEMISTRY REPORTS

APPENDIX E TOXICITY TESTING REPORT

APPENDIX F AGENCY SUITABILITY DETERMINATION

Maintenance Dredging at Coast Guard Station Vallejo

Page v

DISTRIBUTION LIST

US Coast Guard, Civil Engineering Unit Oakland US Army Corps of Engineers, San Francisco District US Environmental Protection Agency, Region 9 San Francisco Regional Water Quality Control Board Dredged Material Management Office Bay Conservation and Development Commission

Maintenance Dredging at Coast Guard Station Vallejo

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ACRONYMS AND ABBREVIATIONS

% percent ± plus or minus °C degrees Celsius µg/kg micrograms per kilogram µg/L micrograms per liter ASTM ASTM International Basin Plan Water Quality Control Plan for the San Francisco Bay Region BCDC San Francisco Bay Conservation and Development Commission BHC benzene hexachloride Brice Brice Engineering C core CCC Criterion Continuous Concentration CETIS Comprehensive Environmental Toxicity Information System CFR Code of Federal Regulations cm centimeter(s) CMC Criterion Maximum Concentration COC chain-of-custody COPC contaminant of potential concern CTR California Toxics Rule CRM Certified Reference Material Cullinan Ranch San Pablo Bay National Wildlife Refuge CWA Clean Water Act cy cubic yard dd/ddd.ddddddd degrees decimal minutes DDD dichlorodiphenyldichloroethane DDE dichlorodiphenyldichloroethylene DDT dichlorodiphenyltrichloroethane DGPS Global Positioning System DMMO Dredged Material Management Office DoD-ELAP U.S. Department of Defense ELAP EC50 median effects concentration EcoAnalysts EcoAnalysts, Inc.

EFH Essential Fish Habitat ELAP Environmental Laboratory Accreditation Program e-mail electronic mail ERL Effects Range-Low ERM Effects Range-Median ft2 square feet g gram(s) GC gas chromatography Green Book Evaluation of Dredged Material Proposed for Ocean Disposal - Testing Manual HASP Health and Safety Plan HDPE high-density polyethylene IAA integrated alternative analysis ID sample identifier ITM Inland Testing Manual

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LC50 median lethal concentration Leviathan Leviathan Environmental Leviathan vessel name LPC limiting permissible concentration m2 square meter(s) MB method blank MET Modified Elutriate Test mg/kg milligram per kilogram mg/L milligram(s) per liter mL milliliter MLLW mean lower low water mm millimeter Montezuma Wetlands Montezuma Wetlands Restoration Project MS matrix spike MSD matrix spike duplicate N/A not applicable NAD83 North American Datum, State Plane Zone 1 NCl nitrogen chloride NH3 ammonia nm nautical miles NOAA National Oceanic and Atmospheric Administration NUAD no unconfined aquatic disposal (not suitable for unconfined aquatic disposal) OD overdredge OPR ongoing precision and recovery OSHA Occupational Safety and Health Administration oz ounce(s) PAH polycyclic aromatic hydrocarbon PCB polychlorinated biphenyl pg/g picograms per gram pH potential of hydrogen Physis Physis Environmental Testing Laboratory PPE personal protective equipment ppt parts per thousand pptr parts per trillion Project USCG Maintenance Dredging Project at Station Vallejo QA quality assurance QAP Quality Assurance Plan QC quality control RCRA Resource Conservation and Recovery Act RPD relative percent difference RWQCB Regional Water Quality Control Board SAP Report Sampling and Analysis Plan Report SET Standard Elutriate Test SF San Francisco SF-09 Carquinez Strait In-Bay disposal site SF-DODs San Francisco Deep Ocean Disposal site SFEI San Francisco Estuary Institute SIM Selective Ion Monitoring

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SM Standard Method SOP Standard Operating Procedure SP solid phase SPP suspended particulate-phase STFATE Short-Term Fate STLC soluble threshold limit concentration Study sediment characterization study SUAD suitability for unconfined aquatic disposal SV Station Vallejo SW Site water SWI sediment water interface TCDD 2,3,7,8-tetrachlorodiobenzo-p-dioxin TCLP toxicity characteristic leaching procedure TEQ toxic equivalent TMDL Total Maximum Daily Load TOC total organic carbon TSS total suspended solids TTLC total threshold limit concentration USACE United States Army Corps of Engineers USCG United States Coast Guard USEPA United States Environmental Protection Agency WQC water quality certification WSP WSP USA Environment & Infrastructure Z-layer 0.5-foot (6-inch) layer of sediment below the 2-foot overdredge allowance that represents the resultant surface post-dredging

Maintenance Dredging at Coast Guard Station Vallejo

Page 1-1

1.0 INTRODUCTION

This Sampling and Analysis Plan Report (SAP Report) provides the results of a sediment characterization study (Study) proposed to support episodic maintenance dredging needed at United States Coast Guard (USCG) Station Vallejo (SV) in Vallejo, California (Figure 1-1). This SAP Report outlines the federally approved procedures that were used to assess the disposal suitability of the proposed dredged materials and the corresponding results of the sediment investigation.

This SAP Report was prepared by WSP USA Environment & Infrastructure (WSP) under contract to the USCG in accordance with the Evaluation of Dredged Materials Proposed for Discharge in Waters of the United States, USEPA-823-B-98-004 (Inland Testing Manual [ITM]) (U.S.

Environmental Protection Agency [USEPA]/U.S. Army Corps of Engineers [USACE], 1998), as supplemented by Public Notice 01-01: Guidelines for Implementing the Inland Testing Manual in the San Francisco Bay Region (USACE/USEPA, 2001) and San Francisco District Public Notice 99-4 Proposed Guidance for Sampling and Analysis Plans (Quality Assurance Project Plans) for Dredging Projects Within the USACE San Francisco District (USACE/USEPA, 1999). This document includes the following elements:

• Introduction

• Site History

• Methods o Dredge Design o Sampling Design o Physical and Chemical Testing o Biological Testing

• Study Results

• Conclusion and Recommendations; and

• Quality Assurance (QA) and Quality Control (QC) Procedures and Review

The Study approach was presented to the Dredged Material Management Office (DMMO) on 6 December 2023. The SAP was approved by the DMMO via electronic mail (e-mail) on 8 December 2023 and through File Number 2008-00049: USCG Station Vallejo, Maintenance Dredging, Episode 2; Sampling and Analysis Plan; DMMO Serial Number 23-081 on 11 December 2023. Appendix A contains all agency comments and correspondence for this Project.

1.1 Project Summary

The USCG Maintenance Dredging Project at SV (Project, Figure 1-2) is required to support berthing and transit of USCG vessels at USCG SV. The ability to conduct these mission-related activities will imminently be impeded by sediment accumulated since the most recent dredging event in 2021; therefore, the USCG plans to dredge SV during the 2024 in-water work window or sooner, if approved by the agencies.

The maintenance dredging design depth for the Project is -10 feet mean lower low water (MLLW) plus a 2-foot overdredge (OD) allowance (to -12 feet MLLW). To support the upcoming episode of maintenance dredging at this site, a bathymetric survey of the permitted area for long-term maintenance dredging was performed by Brice Engineering (Brice) on behalf of the USCG on 6 October 2023. The survey showed that a total of approximately 14,264 cubic yards (cy) of sediment (approximately 600 cy per month) had accumulated within the berthing area since the most recent dredging event occurred approximately 2 years prior (final post-dredge survey

Maintenance Dredging at Coast Guard Station Vallejo

Page 1-2 performed on 9-13 November 2021). For the Study, this sedimentation rate was used to calculate the total volume proposed to be dredged and disposed for this episode to be conducted in mid- 2024. Table 3-1 of this SAP Report contains the actual proposed dredging locations, design depths, and estimated volumes for the Project.

Dredging for the Project will likely consist of dredging the basin from a barge-mounted clamshell/excavator dredge, placing the dredged material onto scows for transport using tugboats, and disposing of the dredged material at an agency-approved placement location. It is expected that the dredging and disposal event may take up to 15 working-days to complete.

Disposal of dredged material in San Francisco Bay is primarily regulated under Section 404 of the Clean Water Act (CWA). The USACE and USEPA each administer specific aspects of Section 404, which established a permit program and technical guidelines to regulate discharges of dredged or fill material. The evaluation of a Section 404 permit application involves determining whether the proposed Project complies with 40 Code of Federal Regulations (CFR) 230 (Guidelines for Specification of Disposal Sites for Dredge or Fill Material) and USACE permit regulations (33 CFR 320–330).

Permitting and Regulatory Information The USCG will perform this dredging episode in accordance with existing permits (Appendix A).

These include USCG multi-year dredging permit SPN-2008-00049N and San Francisco Bay Conservation and Development Commission (BCDC) Consistency Determination Number C2007-005.07. Although the last SV dredging event was performed under California Regional Water Quality Control Board, San Francisco Bay Region (RWQCB) WDID# 2 CW439590, this water quality certification (WQC) was only approved for a single dredging episode; therefore, a new WQC will be necessary for the proposed event.

Agency approval for this event requires coordination with the DMMO. Approval for the event will be based on the results of this Study designed to provide recent physical and chemical characteristics of the proposed dredged materials. Placement suitability will be determined by the Study results in comparison to three potential placement sites the 1) Cullinan Ranch Restoration Project in the San Pablo Bay National Wildlife Refuge (Cullinan Ranch), 2) Montezuma Wetlands Restoration Project (Montezuma Wetlands) and 3) the Carquinez Strait In-Bay disposal site (SF-

09) in accordance with the Integrated Alternatives Analysis for Disposal of Dredged Materials for Coast Guard Projects within San Francisco Bay Region (IAA; USCG 2021). While Montezuma Wetlands was not included as a proposed placement location in the Project SAP, this location was added for consideration through the agency consultation process. Figure 1-3 shows the proposed placement sites. If none of these placement options are considered compatible, the option to dispose the USCG dredged materials at an appropriately permitted upland landfill may be pursued (as needed), based on the Study results.

1.1.1 Purpose and Objectives

The Project purpose is to regain adequate berthing and transit depths for the USCG vessels at USCG SV, which are critical to the USCG’s mission. The Project will be supported by this Study, which has the objective to evaluate the proposed dredged materials for placement suitability in accordance with approved agency testing guidelines.

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USCG Station Vallejo

1 inch = 1 miles 0 10.5

Miles °

Service Layer Credits: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c)

FIGURE 1-1

Project Vicinity Map

United States Coast Guard Station Vallejo Maintenance Dredging

Vallejo, California

Note:

Quadrangle ID: 38122-A3 Mare Island

Page 1-3

Maintenance Dredging at Coast Guard Station Vallejo

Page 1-4

FIGURE 1-2

Project Location Map

United States Coast Guard Station Vallejo Maintenance Dredging

Vallejo, California

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N a p a

R i v e r

Mare Island Causeway

-8

Latitude: 38.110132 (NAD83) Longitude: -122.272297 (NAD83)

Latitude: 38.110363 (NAD83) Longitude: -122.272219 (NAD83)

Latitude: 38.110856 (NAD83) Longitude: -122.272111 (NAD83)

Latitude: 38.111235 (NAD83) Longitude: -122.271585 (NAD83)

Latitude: 38.111191 (NAD83) Longitude: -122.271329 (NAD83)

Latitude: 38.110897 (NAD83) Longitude: -122.27155 (NAD83)

Latitude: 38.110514 (NAD83) Longitude: -122.271697 (NAD83)

Latitude: 38.110215 (NAD83) Longitude: -122.271685 (NAD83)

Latitude: 38.110086 (NAD83) Longitude: -122.272025 (NAD83)

Latitude: 38.111126 (NAD83) Longitude: -122.271848 (NAD83)

Latitude: 38.110576 (NAD83) Longitude: -122.272229 (NAD83)

-5

-15-20-25

-30

0 (MLLW)

-10

50 (MLLW)

0 (MLLW)

-5

-5

0 (MLLW)

-5

-9

-1 -2 -3 -4 -5 -6 -7 -10

°0 10050 Feet

1 inch = 100 feet

Service Layer Credits: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community

#* Existing Outfall Location

Permitted Dredging Area for Long-Term Maintenance (1.5 acres)

Toe of Slope

Existing Bathymetry:

Bathymetry Contour (1ft. interval, MLLW datum)

Bathymetry Contour (5ft. interval, MLLW datum)

Proposed Bathymetry:

Bathymetry Contour (1ft. interval, MLLW datum)

Bathymetry Contour (5ft. interval, MLLW datum)

NOTE: Bathymetry data obtained from survey conducted by ETRAC LLC on 10/05/2022.

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USCG Station Vallejo

S a n P a b l o B a y

Carquinez Strait

Montezuma Wetlands Restoration Site

Grizzly Bay

Suisun Bay

1 inch = 4 miles 0 42

Miles °

Service Layer Credits: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community

FIGURE 1-3

Proposed Disposal Locations

United States Coast Guard Station Vallejo Maintenance Dredging

Vallejo, California

Cullinan Ranch

SF-09 Disposal Site (approximate)

Target SF-09 Reference Collection Area

San Pablo Bay National Wildlife Refuge

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Maintenance Dredging at Coast Guard Station Vallejo

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Maintenance Dredging at Coast Guard Station Vallejo

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1.1.2 Proposed Dredging Volumes and Depths

For Study planning, the proposed Project dredging volume estimated for this event was approximately 23,151 cy.1 This total volume included approximately 18,557 cy of sediment to be removed to the design depth of -10 feet MLLW and approximately 4,594 cy of sediment in the 2-foot OD allowance (to -12 feet MLLW). The dredging event is currently scheduled for August 2024 but may need to be performed sooner based on anticipated berthing and access needs.

Dredging will likely be accomplished using a shallow draft barge-mounted clamshell dredge with scow barges for disposal, depending on the water depth at the time of work.

1.1.3 Proposed and Alternative Placement Options

The USCG prefers to dispose of the material at the most appropriate site based on chemical composition, environmental impact, and cost. However, they are committed to dispose of at least 80 percent of the 2021-2025 maintenance dredging materials from the Station Golden Gate, Station Vallejo, Base Alameda, and Yerba Buena Island (Coast Guard Cutter Aspen Mooring and Approach and Station San Francisco) project sites at an approved and available upland/beneficial reuse site or San Francisco Deep Ocean Disposal site (SF-DODs), and up to 20 percent at the available in-Bay sites in accordance with their IAA (USCG 2021). The IAA, which includes projected dredging volumes from 2021 to 2025 was included as Appendix B in the SAP and is available upon request.

For the Study, samples of the proposed dredged materials were collected at SV with the intent to be tested according to protocols for an unconfined aquatic disposal determination for potential placement at Cullinan Ranch or SF-09; however preliminary results showed that Montezuma Wetlands should also be considered (Figure 1-3). If it is determined by this Study that none of these locations is appropriate for the proposed dredged materials, samples will be evaluated for upland disposal at an appropriately permitted landfill.

Beneficial reuse at Cullinan Ranch is the USCG’s preferred disposal option. Based on correspondence between Steve Carrol of Ducks Unlimited, Inc. and the USCG on 29 August 2023, Cullinan Ranch “is still open for beneficial reuse and has plenty of capacity.” Cullinan Ranch is located approximately 1.74 nautical miles (nm) from the Project site (Figure 1-3).

Cullinan Ranch has specific Waste Discharge Requirements that outline criteria for placement (RWQCB Order Number R2-2010-0108). Acceptance of dredged materials at this site are further described under Specification B.1 of the Regional Board Staff Report Summary Report – Beneficial Reuse of Dredged Materials: Sediment Screening and Testing Guidelines (RWQCB 2000) and within the DMMO guidance document, Guidelines for Implementing the ITM in the San Francisco Bay Region (USACE Public Notice 01-01) with the exception that the water column bioassay simulating in-bay unconfined aquatic disposal shall be replaced with the modified effluent elutriate test, as described in Attachment B of the ITM, for both water column toxicity and chemistry (DMMO suite of metals only).

In case the preferred disposal site is not available at the time of dredging, or the sediment is not compatible for placement, the USCG also evaluated the proposed dredged materials for

1 This volume includes an approximate sedimentation rate of 600 cy per month, or the approximate volume of sediments that were accumulated between November 2021 and October 2023 plus a 10 percent contingency volume to accommodate the potential for heavy rainfall in 2023-2024.

Maintenance Dredging at Coast Guard Station Vallejo Vallejo, California May 2024

Page 1-10 placement at SF-09. The SF-09 in-Bay disposal site is in the Carquinez Strait approximately 3.9 nm from the Project site (Figure 1-3). The Carquinez Strait SF-09 in-Bay placement site is a 1,000-foot by 2,000-foot rectangle, approximately 10-55 feet deep, 0.9 miles west of the entrance to Mare Island Strait in eastern San Pablo Bay.

Once preliminary results were received, a third disposal option, the Montezuma Wetlands in Collinsville, California was added for placement consideration. Montezuma Wetlands are located approximately 23 nm from the Project site.

Selection of the disposal location for the Project will be based on the results of this Study, which compares results to available screening criteria for unconfined aquatic disposal. This Study involves a tiered approach to sampling and analysis that will streamline the disposal determination and consultation process with the DMMO, as outlined in this SAP Report.

1.1.4 Project Timeline and Correspondence with Agencies Regarding SAP Report Approval

The Project SAP was initially presented to the DMMO agencies on 06 December 2023. After the presentation and review, the DMMO agencies recommended minor revisions to the SAP which was then approved on 08 December 2023. Sediment and site water sample collection for the Project took place from 11-14 December 2023 and 21 December 2023. Samples were analyzed between 14 December 2023 and 15 February 2024.

On 06 March 2024, the Draft SAP Report was submitted to the DMMO agencies for consideration at the 20 March 2024 DMMO regular meeting. Following the meeting, the DMMO agencies provided comments and recommendations to the USCG. The Draft SAP Report was revised and resubmitted to the DMMO agencies on 12 April 2024. On 13 May 2024, the USCG received the SUAD determination, in which the DMMO recommended disposal of the proposed dredged materials at an in-Bay disposal site, such as Carquinez Strait (SF-09) or for beneficial reuse at Cullinan Ranch or Montezuma Wetlands. Appendix F contains the SUAD determination from the DMMO agencies.

1.2 Site Description

The USCG SV is located approximately 32 miles northeast of San Francisco in the City of Vallejo, Solano County, California (center point 38.110641 North, -122.271883 West, Figure 1-1). The Project footprint is located within the Vallejo Municipal Marina, on the eastern side of the Napa River/Mare Island Strait, adjacent to Mare Island/Ernest D. Wichels Memorial Causeway. USCG SV is approximately 3 miles upstream from the mouth of the Napa River at Carquinez Strait. Shoaling within the Station boat basin occurs when suspended sediment from the Napa River moves into the sheltered areas, where it slows and settles (BB&E 2021).

USCG SV is a multi-mission small boat station for emergency response, search and rescue operations, and maritime law enforcement. The area of responsibility covers San Pablo Bay north of the Richmond Bridge, Petaluma River, Napa River, and Suisun Bay to the Antioch Bridge and up to Suisun City. Facility buildings line the shore of the Vallejo Marina, along with restaurants, a marine mechanic shop, and associated parking lots. Two outfalls discharge into the vicinity of the proposed dredging area (Figure 1-2). These outfalls collect stormwater from various areas of SV and surrounding sites and discharge into the Marina.

Maintenance Dredging at Coast Guard Station Vallejo

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The approved maintenance depth at SV is -10 feet MLLW plus a 2-foot OD allowance (to -12 feet MLLW) and the permitted dredging area for long term maintenance is approximately 59,560 square feet (ft2; 1.37 acres). The most recent dredging event at SV was performed from 9 to 13 November 2021.

1.3 Scope of Work

This SAP Report details the results of the sediment collection and testing program to support the 2024 episodic maintenance dredging event. The primary disposal option to be evaluated for the Project is beneficial reuse at Cullinan Ranch, Montezuma Wetlands, or SF-09 in the Carquinez Strait (Figure 1-3). If none of these options are deemed appropriate for the Project dredged materials, additional analytical testing will be performed to determine whether the sediment can be disposed of at an appropriately permitted upland landfill. Program elements included the following:

• Preparation of a Project-specific SAP for agency review and approval,

• Adoption of a Health and Safety Plan (HASP), including all requirements in Occupational Safety and Health Administration (OSHA) 29 CFR 1910,

• Field mobilization and collection of six sediment core samples to the maintenance dredging design depth, plus a 2-foot OD allowance and a 0.5-foot (6-inch) Z-layer in accordance with the procedures outlined in the SAP,

• Compositing the six individual samples for chemical, physical, and toxicological analyses,

• Collection of site water for elutriate testing,

• Collection of a reference sediment sample at the SF-09 reference site,

• Submission of samples to accredited laboratories for physical, chemical, and toxicological analyses,

• QA/QC review of data,

• Analysis of sediment chemistry and toxicity results,

• Preparation of this detailed SAP Report for submission to the DMMO, and

• Convening of a sediment disposal suitability meeting with the DMMO to present a detailed discussion of the test results.

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2.0 SITE HISTORY

Sediment testing results for material collected for regular updates of the permit and for unconfined disposal have consistently indicated that the material is clean and suitable for unconfined aquatic disposal, near-shore placement, and/or beach replenishment. Sediment testing results for the 2013, 2018, and 2021 dredging events are included in Appendix A, and a sampling map is shown on Figure 2-1.

Appendix A also contains historical permits for the Project that would be reapplied for to support the current dredging effort.2 The recent dredging history, including USACE permit numbers, volumes, design depths, contaminants of concern, and placement locations for this site, is presented in Table 2-1.

Table 2-1. Dredging Site History

Dredging Year Permit Number

Total Volume Dredged

(cy)1

Dredging Depth

(feet MLLW) COPC Placement Site (Ocean, Upland, Beach, etc.)

2021 2008-00049N 10,313 -12 None Beneficial reuse at Cullinan Ranch Wetlands Restoration Site

2018 2008-00049N 15,600 -12 None Beneficial reuse at

Cullinan Ranch Wetlands Restoration Site, SF-09

2013 2008-00049N 8,850 -12 None SF-09 Notes:

COPC = contaminant of potential concern; cy = cubic yard(s); MLLW = mean lower low water; USCG = United States Coast Guard 1 Volumes are approximate.

During the 2021 event, approximately 10,313 cy of sediment was dredged within the authorized footprint and transported to the Cullinan Ranch Restoration Project for beneficial reuse. Prior to this event, maintenance dredging was conducted at USCG SV in the fall of 2018 and removed approximately 15,600 cy. For the 2018 event, approximately 1,800 cy was disposed in-Bay at SF-09 in Carquinez Strait and approximately 13,800 cy of material was used beneficially at the Cullinan Ranch restoration site. In 2013, approximately 8,850 cy were dredged from the footprint and placed at SF-09.

2.1 Summary of Prior Sediment Characterization Results

The primary findings for sediments evaluated in 2020 for the 2021 dredging event are outlined as follows:

1. Sediments were characterized as fine-grained depositional material.

2. In general, the sediments exhibited low concentrations of chemical constituents.

3. Sediment chemistry levels were generally below the Effects Range-Low (ERL) guideline values and the San Francisco Bay ambient concentrations.

4. Sediment chemistry levels were all below the Cullinan Ranch disposal site criteria.

2 Due to file size, copies of these historical permits can be provided upon request.

Maintenance Dredging at Coast Guard Station Vallejo

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5. Mercury values exceeded the bioaccumulation trigger (Site sample result = 0.347 milligram per kilogram (mg/kg); bioaccumulation trigger = 0.332 mg/kg) criteria value.

However, the values were below the Total Maximum Daily Load (TMDL) limit for San Francisco Bay ambient sediment concentrations (0.47 mg/kg) and were also below the Cullinan Ranch disposal site criteria guideline values (BB&E 2021).

6. Based on the absence of any significant adverse biological effects and contaminant concentrations that were below the dredge material acceptance criteria for placement at Cullinan Ranch and SF-09, sediments proposed for dredging from the USCG SV were not expected to elicit significantly adverse ecological impacts within Cullinan Ranch or SF-09.

The primary findings for sediments evaluated for the 2018 dredging event are outlined as follows:

1. Sediments were characterized as fine-grained depositional material.

2. In general, the sediments exhibited low or non-detect concentrations of chemical constituents.

3. Sediment chemistry levels were generally above SF-09 reference site conditions.

4. Sediment chemistry levels were generally below the ER-L guideline values and the San

Francisco Bay ambient concentrations.

5. Sediment chemistry levels were generally below the Cullinan Ranch use as cover guideline values except for metals, which were slightly elevated above guideline values.

6. Modified Elutriate Test (MET) metals concentrations were below the environmental screening levels.

7. Sediment chemistry levels were all below the available trigger levels for bioaccumulation.

8. The toxicity analyses exhibited no acute sediment, standard elutriate, or MET elutriate toxicity for any of the tested organisms (Arcadis 2018).

9. Based on the absence of any significant adverse biological effects and contaminant concentrations that were below the dredged material acceptance criteria for placement at Cullinan Ranch and SF-09, sediment proposed for dredging from the USCG SV were not expected to elicit significantly adverse ecological impacts within Cullinan Ranch or SF-09.

FIGURE 2-1

Historical Sampling Locations

United States Coast Guard Station Vallejo Maintenance Dredging

Vallejo, California

Path: X:\US\USPDX800-POR\ClientData\USCG - Coast Guard\336010031 - USCG Mooring Ballast Point\Vallejo\Figure 2-1 – Historical Sampling Locations.mxd, USSD715014 11/13/2023

!P

!P

!P

!P

!P

!U

!U

!U

!U

N a p a

R i v e r

Mare Island Causeway

-5

-15-20-25

-30

0 (MLLW)

-10

50 (MLLW)

0 (MLLW)

-5

-5

0 (MLLW)

-5

VN1-1

VN1-2

VN1-3

VN1-4

VN1-5

A-1

A-2

A-3

A-4

B-1

B-2

B-4

VAL-01

VAL-02

VAL-03

VAL-04

°0 10050 Feet

1 inch = 100 feet

Service Layer Credits: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community

!. Sediment Core (USCG STA Vallejo, 2020)

!< Sediment Core (USCG STA Vallejo & City of Vallejo, 2018)

!P Sediment Core (Vallejo Marina, 2012)

!U Sediment Core (USCG STA Vallejo, 2008)

#* Existing Outfall Location

Bathymetry Contour (1ft. interval, MLLW datum) Bathymetry Contour (5ft. interval, MLLW datum) Permitted Dredging Area for Long-Term Maintenance (1.5 acres)

Toe of Slope

NOTE: Bathymetry data obtained from survey conducted by ETRAC LLC on 10/05/2022.

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3.0 METHODS

This section provides details on the proposed maintenance dredging volumes and target sample collection depths, discusses the procedures used to access the collection sites, and describes the methods and materials used to collect, composite, handle, and archive sediment samples for the proposed Study. The Study implemented Tier II chemical and physical testing to allow the USCG and agencies to verify that the proposed dredged materials are suitable to be used at an available approved beneficial reuse site (e.g., Cullinan Ranch or Montezuma Wetlands) or for open water disposal at SF-09.

3.1 Dredging Design

Dredging design plans by Brice are included in Appendix A. The approximate area proposed for long-term maintenance dredging over the 10-year permit cycle is approximately 59,560 ft2 (1.37 acres). The proposed dredging location, design depth, and estimated dredging volumes are summarized in Table 3-1. Note that these dredging volumes are based on a 6 October 2023 survey and should be considered approximate as the actual sediment volumes at the time of dredging may be slightly higher or lower than those presented. For the Study, one composite was prepared of the proposed dredged materials for testing (Figure 3-1). The dredging design includes a 3:1 slope, as shown in the cross-sections on Figure 3-2.

Table 3-1. Station Vallejo Proposed Dredging Locations, Design Depths, and Volumes

Maintenance Dredging Location

Composite Area Approximate

Permitted Dredging Area

(acres)

Design Depth

(feet MLLW)

Estimated Dredge Volume to Design Depth

(cy)

Estimated 2-foot OD

Volume (cy)

Estimated Total Volume

Per Composite Area (cy)1

USCG Station Vallejo Total 1.37 −10.0 18,557 4,594 23,151

Notes:

cy = cubic yard(s); MLLW = mean lower low water; OD = overdredge; USCG = United States Coast Guard

1. Includes the total volume with the 2-foot overdredge allowance.

2. The proposed dredging volume used to design the Study is estimated and was determined using a 6 October 2023 bathymetric survey. The dredged material to the design depth includes an estimated sedimentation rate of 600 cy per month to estimate accumulation that may occur between the 2023 bathymetric survey and the proposed dredging event. A 10 percent contingency is also included to accommodate the potential for heavier than average rainfall in 2023-2024.

3.2 Sampling Design

Sediment sampling for the Study was designed to ensure that representative samples were collected for the proposed dredge sites. A reference sample was collected at SF-09 (38.06296291, -112.26707036) on 11 December 2023 (Figure 3-2) and six locations within the proposed dredging area at SV were sampled using a vibracore on 12 and 13 December 2023 (Figure 3-1, Table 3-2). In addition to sediments, site water used to prepare elutriate samples were also collected on 13 and 21 December 2023.

Sediment collection followed the guidance in Methods for Collection, Storage and Manipulation of Sediments for Chemical and Toxicological Analyses: Technical Manual (USEPA, 2001).

Sediment cores collected from each of the six proposed sampling sites were collected from the sediment water interface (SWI) to the design depth plus a 2-foot OD allowance. Samples were

Maintenance Dredging at Coast Guard Station Vallejo

Page 3-2 collected using a vibracore sampler in accordance with the methods described in Section 3.2.7.1 at the sampling locations shown on Figure 3-1 and listed in Table 3-2.

Any accumulated sediment that is deposited within the proposed dredging footprint between the time of sampling and dredging activity will be assumed to have the same chemical composition unless a significant event occurs.

3.2.1 Sampling and Testing Objectives

The objective of the Study was to determine the placement location for the proposed Project dredged materials and to consider any impacts dredging or disposal operations may have on sediments and water quality of the SV local ecosystem and the final placement site. Sample collection was documented using vibracore logs and photography. Vibracore logs are in Appendix B, and photographs of cores are in Appendix C.

3.2.2 Sample Identification

Samples were identified by the sampling location (SV or SF-09 Reference), the year in which the sample was collected (2023, “-23-“), the sample type, and the type of sample (e.g., core = C; site water = SW). For QA/QC, a duplicate sample (SV-23-DUP) was also collected for chemical analyses. In addition, any Z-layer samples collected were labeled with the same sample identifier and appended with a “Z.”

3.2.3 Core Sample Locations and Depth

Table 3-2 is an overview of positioning, sample collection times, mudline elevations, Project depths, target penetration depths, actual penetration depths, analysis lengths, and general notes for each core. The actual penetration depth is the actual penetration of the vibracore into the sediment, which was attempted to the target core length. The target core length is calculated by subtracting the mudline elevation measured in the field from the design depth plus the 2-ft OD allowance. Samples of the dredged material were collected to the design depth of -10 feet MLLW plus a 2-foot OD allowance to -12 feet MLLW.

As required by the Essential Fish Habitat (EFH) agreement (USACE and USEPA 2011, USACE and USEPA 2012), an undisturbed 6-inch “Z-layer” immediately below the OD at each sample location was also collected by penetrating the vibracore an additional 1-foot beyond the OD. This 6-inch Z-layer sediment was archived for future testing that will only be required if deemed necessary by the DMMO based on a review of the results of the chemical and physical tests presented in this SAP Report. Any sediment collected below the Z-layer was discarded. Z-layers were recovered for four of the six samples. No Z-layer was recovered for samples SV-23-C3 and SV-23-C5. All samples were stored at 4 degrees Celsius (°C) prior to test initiation.

Actual Sampling Locations United States Coast Guard Station Vallejo

Maintenance Dredging Vallejo, California

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Mare Island Causeway

N a p a

R i v e r

-5 -10

-20-25

-30

0 (MLLW)

-15

50 (MLLW)

0 (MLLW)

-5

-5

0 (MLLW)

0 (MLLW)

-5

-9

-1 -2 -3 -4 -5 -6 -7 -8 -10

SV-23-C3

SV-23-C1

SV-23-C2

SV-23-C6

SV-23-C5

SV-23-C4

SV-23-SW

SV-23-C1

SV-23-C2

SV-23-C3

SV-23-C4

SV-23-C5

SV-23-C6

SV-23-SW1

SV-23-SW2

Service Layer Credits: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community

#* Existing Outfall Location Permitted Dredging Area for Long-Term Maintenance (1.5 acres)

Toe of Slope

Proposed Bathymetry:

Bathymetry Contour (1ft. interval, MLLW datum) Bathymetry Contour (5ft. interval, MLLW datum) Proposed Dredging Footprint

Existing Bathymetry:

Bathymetry Contour (1ft. interval, MLLW datum) Bathymetry Contour (5ft. interval, MLLW datum)

!. Actual Sediment Sample Location !. Actual Site Water Sample Location "/ Proposed Sediment Sample Location "/ Proposed Site Water Sample Location

FIGURE 3-1°0 7537.5

Feet

1 inch = 75 feet

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Table 3-2. Vibracore Collection Log

Sample Identifier Core

Attempts Required

Latitude (dd.dddddd)

Longitude (ddd.dddddd) Date Time

Project Depth (Plus 2 foot OD

Plus 1 foot for Z- Layer Recovery)

Mudline Elevation

(feet MLLW)

Target Penetration

(feet)

Actual Penetration

(feet) Recovered Core

Length (feet) Additional Notes

SV-23-C1 1 38.111087 -122.271366 12/12/2023 8:45 -13.0 -5.3 7.7 9.9 9.7 Lost material in catcher, small amount around 0.2 feet.

SV-23-C2 1 38.110942 -122.271804 12/12/2023 13:15 -13.0 -5.7 7.3 8.0 7.3 Soft plug.

SV-23-C3 1 38.110722 -122.272163 12/12/2023 14:10 -13.0 -4.0 9.0 9.0 8.0 Small soft plug. No Z-layer. Sediment is too soft. Fell out.

SV-23-C3 2 38.110719 -122.272165 12/12/2023 14:30 -13.0 -4.2 8.8 9.8 8.0 Combined with Attempt #1. Collected for Z-layer recovery. Result was the same.

SV-23-C4 1 38.110472 -122.272031 12/13/2023 10:25 -13.0 -6.9 6.1 8.6 7.4 No comments recorded.

SV-23-C5 1 38.110329 -122.271719 12/12/2023 10:25 -13.0 -2.4 10.6 10.5 7.3 No plug. Lost bottom of core on retrieval. Core rejected, not 75% recovery. RCRA archive only.

SV-23-C5 2 38.110362 -122.271720 12/12/2023 11:00 -13.0 -2.7 10.3 11.0 7.2 Small plug. Not 75% recovery. No sample.

SV-23-C5 3 38.110324 -122.271777 12/12/2023 11:40 -13.0 -2.8 10.2 11.0 8.5 No plug. 78% recovery. No Z-layer.

SV-23-C6 1 38.110263 -122.272217 12/13/2023 8:50 -13.0 -5.1 7.9 8.9 7.5 No comments recorded.

Notes: dd/ddd.ddddddd = degrees decimal minutes; OD = overdredge; MLLW = mean lower low water; % = percent; RCRA = Resource Conservation and Recovery Act (landfill)

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C a r q u i n e z S t r a i t

X: 6052094.61 Y: 2214939.53

X: 6054064.31 Y: 2215286.83

X: 6054237.91 Y: 2214302.03

X: 6052268.31 Y: 2213954.73

X: 6052181.46 Y: 2214447.12

X: 6054151.11 Y: 2214794.43

1 inch = 1,000 feet 0 1,000500

Feet °

Service Layer Credits: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community

FIGURE 3-2

SF-09 Reference Sediment Collection Site United States Coast Guard Station Vallejo

Maintenance Dredging Vallejo, California

_̂ SF-09 Reference Collection Location

SF-09 Disposal Site (approximate)

Target SF-09 Reference Collection Area

NOTE: Coordinates shown are in NAD83, California State Plane Zone 3, feet.

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3.2.4 Reference and Control Sediment Sample Collection

Reference sediment was collected in the southeastern half of the designated SF-09 reference site (approximate collection location latitude 38.062963, longitude -112.267070) that has been used for numerous dredged material bioassays (Figure 3-2).

Negative control sediments were used for solid phase (SP) toxicity exposures. The negative control (“home”) sediments were collected at the same location and at the same time as the test organisms. Negative control sediment exposures were used to determine the health of the test organisms during the laboratory exposure period. For the tests to be considered valid, organism performance met the specific control criteria of greater than 90 percent mean survival in the SP tests. Survival at these levels attests to the suitability of the organisms for testing purposes.

Negative control sediments were collected by the test organism supplier and sent to the EcoAnalysts, Inc. (EcoAnalysts) toxicity testing laboratory in Port Gamble, Washington, along with each batch of test organisms. All control sediments were stored at 4°C prior to test initiation.

3.2.5 Composite Areas

Sediments collected for the Study area were tested as one composite sample comprising six core samples (Figure 3-1). To adequately characterize sediment quality and collect enough material to run all proposed analyses, multiple core samples were collected at several of the proposed sampling locations (Table 3-2).