FIO-Sampling_and_Analysis_Report_Final_San_Luis_Rey_River_Sept_2016.pdf

SAMPLING AND ANALYSIS REPORT

San Luis Rey River Geotechnical and Environmental Investigation Project

Task Order No. 0013, USACE Contract No. W912PL-11-D-0015

Prepared for:

U.S. Army Corps of Engineers

Los Angeles District Los Angeles, California

Prepared by:

Diaz•Yourman – GeoPentech – Kinnetic Laboratories/ Joint Venture 1616 E. 17th Street

Santa Ana, CA 92705

September 2016

GeoPentech i

DISTRIBUTION LIST

Mr. Jeffrey Devine, Technical Manager U. S. Army Corps of Engineers, Los Angeles District Jeffrey.D.Devine@usace.army.mil

Mr. Saroj Weeraratne Geotechnical Leader Diaz Yourman Saroj@diazyourman.com

Larry Smith, Technical Manager U. S. Army Corps of Engineers, Los Angeles District Lawrence.J.Smith@usace.army.mil

Mr. Ken Kronschnabl KLI Project Manager Kinnetic Laboratories, Inc.

kkronsch@kinneticlabs.com

Mr. Thomas Keeney, Senior Terrestrial Ecologists/Biological Sciences Manager U. S. Army Corps of Engineers, Los Angeles District Thomas.w.keeney@usace.army.mil

Mr. Spencer Johnson Field Operations Manager Kinnetic Laboratories, Inc.

sjohnson@kinneticlabs.com

Mr. Paul Beaver, Geotechnical Office U. S. Army Corps of Engineers, Los Angeles District paul.r.beaver@usace.army.mil

Ms. Amy Howk KLI QA/QC Management Kinnetic Laboratories, Inc.

ahowk@kinneticlabs.net

Ms. Raina Fulton Project Management Division U. S. Army Corps of Engineers, Los Angeles District Raina.Fulton@usace.army.mil

Mr. Jon Toal Health and Safety Management Kinnetic Laboratories, Inc.

jtoal@kinneticlabs.com

Mr. Christopher Diaz Geotechnical Manager Diaz Yourman & Associates chris@diazyourman.com

Carla Hollowell Client Services Director Eurofins Calscience CarlaHollowell@eurofinsUS.com

Mr. Allen Yourman Joint Venture Project Manager Diaz Yourman Associates, GeoPentech, and Kinnetic Laboratories Joint Venture Allen@diazyourman.com ii

San Luis Rey River Geotechnical and Environmental Investigation Project

Task Order No. 0013, USACE, Contract No. W912PL-11-D-0015

TABLE OF CONTENTS

Page No.

1.0 INTRODUCTION

2.0 ROLES AND RESPONSIBILITIES

3.0 METHODS

3.1 Construction Design

3.2 Sampling and Testing Design

3.2.1 Sampling and Testing Approach

3.2.2 San Luis Rey River Sample Identification, Composite Areas, Sediment Collection and Testing

3.2.3 Geotechnical Samples and Testing

3.2.4 Summary of San Luis Rey River Testing and Evaluation Sequence

3.2.5 Evaluation Guidelines

3.3 Field Sampling Protocols

3.3.1 Positioning and Elevation Measurements

3.3.2 Hand Auger Sampling Methods

3.3.3 Environmental Constraints

3.3.4 Equipment Decontamination

3.3.5 Detailed Soils Log

3.3.6 Documentation and Sample Custody

3.4 Laboratory Testing Methods

3.4.1 Geotechnical Testing

3.4.2 Bulk Sediment Chemical Analyses

3.4.3 Bioassay Analyses

4.0 RESULTS

4.1 Sediment Physical Results

4.2 Sediment Chemical Results

5.0 DISCUSSION

5.1 Sediment Observations and Sediment Mapping

5.2 Sediment Grain Size

5.3 Bulk Sediment Chemistry

6.0 QUALITY CONTROL SUMMARY

6.1 Field Sampling Quality Management

6.2 Analytical Chemistry QA/QC

6.0 REFERENCES CITED

iii

APPENDICES

APPENDIX A – Core Photographs APPENDIX B – Field Data Logs APPENDIX C – Analytical Laboratory Reports APPENDIX D – Soil Logs of Sediment Physical Characteristics APPENDIX E – Grain Size Distribution Curves and Other Physical Data APPENDIX F – Analytical Quality Assurance/Quality Control Report APPENDIX G – Physical Compatibility Analysis between the San Luis Rey River and Oceanside Beach (USACE, Los Angeles District, 2016).

LIST OF TABLES

Page No.

Table 1. Project Team and Responsibilities Table 2. Key Project Contacts Table 3. Final Sampling Locations, 2016 River Bottom Elevations, and Sampling Depths for

San Luis Rey River Flood Control Project Composite Area A Table 4. Final Sampling Locations, 2016 River Bottom Elevations, and Sampling Depths for

San Luis Rey River Flood Control Project Composite Area B Table 5. Final Sampling Locations, 2016 River Bottom Elevations, and Sampling Depths for

San Luis Rey River Flood Control Project Composite Area C Table 6. Final Sampling Locations, 2016 River Bottom Elevations, and Sampling Depths for

San Luis Rey River Flood Control Project Composite Area C Table 7. PID readings from Selected Boreholes Table 8. Sediment Analytical Methods and Quantitation Limits Achieved Table 9. Liquid Phase Analytical Methods and Quantitation Limits Achieved Table 10. 2016 San Luis Rey River Sieve Analysis Weighted Average Data for the Individual

Locations and Composite Areas Table 11. Sediment Chemistry Results for the San Luis Rey River with Applicable Screening

Levels in Solids for Conventional and Inorganic Analyses Table 12. Sediment Chemistry Results for the San Luis Rey River with Applicable Screening

Levels in Solids for Organic Analyses Table 13. Sediment Results in Wet Weight for Title 22 TTLC Constituents Table 14. Title 22 Bioassay Results for San Luis Rey Sediments Table 15. TCLP Results with Applicable Screening Levels for Soluble Inorganic and Organic

Analytes in Liquid Phase Table 16. Quality Control Summary for Field Sediment Sampling Table 17. Counts of QC records per Chemical Category Table 18. Final QC Qualification Applied to Sample Results iv

LIST OF FIGURES

Page No.

Figure 1. Vicinity of San Luis Rey River Sediment Removal Project Area Figure 2. Project Limits for the San Luis Rey River Flood Control Sediment Removal Project. 3 Figure 3. Final Sampling Locations and 2016 Topographic Data for Reach 120+00 to 140+00 of the San Luis Rey River Figure 4. Final Sampling Locations and 2016 Topographic Data for Reach 140+00 to 165+00 of the San Luis Rey River Figure 5. Final Sampling Locations and 2016 Topographic Data for Reach 165+00 to 190+00 of the San Luis Rey River Figure 6. Final Sampling Locations and 2016 Topographic Data for Reach 190+00 to 215+00 of the San Luis Rey River Figure 7. Location of the Proposed Stockpile Area for the San Luis Rey River Excavated

Sediments Figure 8. Approximate Stockpile Areas for the San Luis Rey River Excavated Sediments Figure 9. Least Bell’s Vireo Preliminary 2016 territories with a 50-foot Buffer Figure 10. Composite Weighted Average Grain Size Curve for all San Luis Rey River Samples

Compared to the Grain Size Compatibility Envelope for Oceanside Beach Figure 11. Removal area (pink) for unsatisfactory sediment for Reach 120+00 to 140+00 of the

San Luis Rey River (only area in entire project removal limits that is unsatisfactory).

v

LIST OF ACRONYMS

AHA Activity Hazardous Analysis MS Matrix Spike ASTM American Society for Testing and Materials MSD Matrix Spike Duplicate BGS Below Ground Surface MSL Mean Sea Level BLK Method or Procedural Blank NA Not Applicable BS Blank Spike ND Not Detected

BSD Blank Spike Duplicate NOAA National Oceanic and Atmospheric Administration

Cal/EPA California Environmental Protection Agency OEHA Office if Environmental Hazard Assessment CCR California Code of Regulations PAH Polyaromatic Hydrocarbon CD Compact Disc PCB Polychlorinated Biphenyl CDFW California Department of Fish andWildlife PDS Post Digestion Spike CESPD Corps of Engineers South Pacific Division PDSD Post Digestion Spike Duplicate CHHSL California Human Health screening Level PID Photoionization Detector COC Chain of Custody PPB Parts Per Billion CSLC California State Lands Commission PPM Parts Per Million CV Coefficient of Variation PRG Preliminary Remediation Goals cy Cubic Yards PVC Polyvinyl Chloride CRM Certified Reference Material QA Quality Assurance DDD Dichlorodiphenyldichloroethane QC Quality Control DDE Dichlorodiphenyldichloroethylene QUAL Qualifier DDT Dichlorodiphenyltrichloroethane RBC Risk-Based Concentration DGPS Differential Global Positioning Satellite RL Reporting Limit DQO Data Quality Objectives RPD Relative Percent Difference

DTSC Department of Toxic Substances Control RSLs Regional Screening Levels for Cleanup of Superfund Sites

DUP Laboratory Replicates SC-DMMT Southern California Dredge Material Management Team

ERL NOAA Effects Range Low SDRWQCB San Diego Regional Water Quality Control Board

ERM NOAA Effects Range Medium SLRR San Luis Rey River ESL Environmental Screening Level SOPs Standard Operating Procedures GPS Global Positioning Satellite SRM Standard Reference Material

HHMSSL Human Health Medium – Specific Screening Levels STLC Title 22 Soluble Threshold Limit

Concentration HDPE High-density Polyethylene SURR Surrogate Analysis ILCR Incremental Lifetime Cancer Risk SWQCB State Water Resources Control Board ITM Inland Testing Manual TCLP Toxicity Characteristic Leaching Procedure HI Hazard Index TOC Total Organic Carbon HQ Hazard Quotient TPH Total Petroleum Hydrocarbons LC50 Lethal Does 50% Concentration TRPH Total Recoverable Hydrocarbons LCL Lower Control Limit TTLC Title 22 Total Threshold Limit Concentration LCS Laboratory Control Spike UCL Upper Control Limit LDPE Low-density Polyethylene USACE U.S. Army Corps of Engineers LSD Least Significant Difference USEPA U.S. Environmental Protection Agency MDL Method Detection Limit USCS Unified Soil Classification System MLLW Mean Lower Low Water WDRs Waste Discharge Requirements

San Luis Rey River Geotechnical and Environmental Investigation Project

Task Order No. 0012, USACE Contract No. W912PL-11-D-0015

1.0 INTRODUCTION

Sediment buildup along a 1.8-mile reach of the San Luis Rey River (SLRR) in Oceanside, CA (Figures 1 and 2) needs to be removed in order to improve flood control along that reach by restoring the elevation of the river bottom back to its 1993 as-built invert elevations. The U.S.

Army Corps of Engineers (USACE), Los Angeles District proposes to excavate sediment in that reach, and if compatible, reuse it primarily as beach nourishment material at nearby City of Oceanside beaches. Total volume of sediments to be removed is approximately 200,000 cubic yards (cy) and approximately 120,000 to 150,000 cy of that is beach compatible sandy sediment.

If not beach compatible, then the sediment will have secondary use as fill material by the City of Oceanside. The 50,000 to 80,000 cy of beach incompatible material consists or the top eight inches of material that will be stripped across the entire project footprint during clearing and grubbing operations and any material that has grain size gradations that do not fit within the finest and coarsest limits of the receiving beach. Any vegetation debris will be separated from the incompatible material and mulched. The last and least preferred use of the incompatible sediment would be for use as cover or fill material at various local San Diego County permitted solid waste landfills. After excavation and before final use determination, the sediment will be stockpiled at the City of Oceanside owned property occupied by the El Corazon composting facility of El Corazon.

The purpose of this investigation was to determine the physical properties of sediments to be removed and to determine if there is existing chemical contamination in any of the sediments that may affect placement alternatives. Results of this initial investigation will be used during preparation of design and specifications to get a better understanding of suitability for each of the different placement alternatives and to determine future testing requirements once the material is removed and stockpiled. An additional purpose of this investigation is to confirm that the sediments will not have any adverse effects to human health while stockpiled.

This report has been prepared on behalf of the U.S. Army Corps of Engineers, Los Angeles District to detail the sampling procedures performed and quality assurance/quality control (QA/QC) results for the sampling and testing of sediments from the sediment removal reach of the San Luis Ray River. This work is being performed under Task Order No. 0013, USACE Contract No. W912PL- 11-D-0015.

Figure 1. Vicinity of San Luis Rey River Sediment Removal Project Area.

Figure 2. Project Limits for the San Luis Rey River Flood Control Sediment Removal Project.

2.0 ROLES AND RESPONSIBILITIES

Project responsibilities and key contacts for this sediment characterization program are listed in Tables 1 and 2. Diaz Yourman and Associates (DYA) is responsible for overseeing the project and for core logging and geotechnical testing and reporting. Strongarm Environmental Field Services conducted the actual borings. Kinnetic Laboratories Inc. (KLI) took the environmental samples, with all associated documentation, and provided reporting services. Analytical chemical testing of sediments for this project was primarily carried out by Eurofins Calscience (Cal-ELAP No. 2944).

Table 1. Project Team and Responsibilities

Responsibility Name Affiliation

Project Planning and Coordination

Raina Fulton Jeffrey Devine

Larry Smith Christopher Diaz Ken Kronschnabl

USACE

USACE

USACE

Diaz-Yourman Kinnetic Laboratories

Sampling and Analysis Plan (SAP) Preparation Ken Kronschnabl Christopher Diaz

Kinnetic Laboratories Diaz-Yourman

Biologically Sensitive Areas Thomas Keeney USACE

Field Sample Collection and Transport

Tim Fleming Kelly Shaw Juan Osorio

Darren Zuidema

Kinnetic Laboratories Diaz Yourman

Strong Arm Env.

Strong Arm Env.

Geotechnical Investigation

Jeffrey Devine Paul Beaver Chris Diaz Kelly Shaw

USACE

USACE

Diaz-Yourman Diaz-Yourman

Health and Safety Officer and Site Safety Plan Jon Toal Chris Diaz

Kinnetic Laboratories Diaz Yourman

Laboratory Chemical Analyses Carla Hollowell

Katie Scott Amy Howk

Eurofins Kinnetic Laboratories Kinnetic Laboratories

QA/QC Management Analytical Laboratory QA/QC

Danielle Gonsman Amy Howk

Carla Hollowell

Kinnetic Laboratories Kinnetic Laboratories

Eurofins

Technical Review

Pat Kinney Jeffrey Devine

Christopher Diaz Larry Smith

Joe Ryan

Kinnetic Laboratories

USACE

Diaz-Yourman

USACE

USACE

Final Report Ken Kronschnabl Christopher Diaz

Kinnetic Laboratories Diaz-Yourman

Suitability Determinations Jeffrey Devine Lawrence Smith

USACE

USCAE

Agency Coordination Jeffrey Devine Lawrence Smith

USACE

USCAE

Table 2. Key Project Contacts Ms. Raina Fulton USACE Project Manager Project Management Division U. S. Army Corps of Engineers, Los Angeles

District 915 Wilshire Blvd.

Los Angeles, Ca. 90017 Tel. (213) 452-3998 Raina.Fulton@usace.army.mil

Jeffrey Devine USACE Project Technical Manager Geology and Investigations Section U. S. Army Corps of Engineers, Los Angeles District 915 Wilshire Blvd.

Los Angeles, Ca. 90017 Tel. (213) 452-3579 Jeffrey.D.Devine@usace.army.mil

Larry Smith USACE Project Technical Manager U. S. Army Corps of Engineers, Los Angeles District 915 Wilshire Blvd.

Los Angeles, Ca. 90017 Tel. (213) 452-3876 Kirk.C.Brus@usace.army.mil

Mr. Paul Beaver Geotechnical Project Engineer U. S. Army Corps of Engineers, Los Angeles District 915 Wilshire Blvd.

Los Angeles, Ca. 90017 Tel. (213) 452-3588 paul.r.beaver@usace.army.mil

Mr. Thomas Keeney Project Senior Terrestrial Ecologists/Biological Sciences Manager Environmental Resources Branch - U. S. Army Corps of Engineers, Los Angeles District 915 Wilshire Blvd.

Los Angeles, Ca. 90017 office: 213-452-3875; mobile: 213-304-7796 Thomas.W.Keeney@usace.army.mil

Ken Kronschnabl Project Manager - Sampling/Testing Kinnetic Laboratories, Inc. (KLI) 307 Washington St.

Santa Cruz, CA 95060 Tel. (831) 457-3950 kkronsch@kinneticlabs.com

Chris Diaz Project Manager - Geotechnical Investigations Diaz.Yourman & Associates 1616 East 17th Street Santa Ana, CA 92705-8509 Tel. (714) 245-2920 chris@diazyourman.com

Michele Castro Business development Manager Eurofins Calscience, Inc.

7440 Lincoln Way Garden Grove, CA 92841-1427 Tel.: (949) 870-8766 MicheleCastro@eurofinsUS.com

Timothy Fleming Environmental Testing Field Lead Kinnetic Laboratories, Inc. (KLI) 5225 Avenida Encinas, Suite H Santa Cruz, CA 92008 Tel. (760) 438-8968 tfleming@kinneticlabs.net

Allen Yourman Joint Venture Project Manager Diaz Yourman Associates, Geopentech, and Kinnetic Laboratories Joint Venture 1616 East 17th Street Santa Ana, CA 92705-8509 Tel. (714) 245-2920 Allen@diazyourman.com

Amy Howk KLI QA/QC Management Kinnetic Laboratories, Inc.

307 Washington St.

Santa Cruz, CA 95060 Tel. (831) 457-3950 ahowk@kinneticlabs.net

Kelly Shaw Field Contact Diaz.Yourman & Associates 1616 East 17th Street Santa Ana, CA 92705-8509 Tel. (562) 787-3165 mailto:Jeffrey.D.Devine@usace.army.mil mailto:paul.r.beaver@usace.army.mil mailto:Thomas.W.Keeney@usace.army.mil mailto:kkronsch@kinneticlabs.com mailto:MicheleCastro@eurofinsUS.com mailto:Allen@diazyourman.com

3.0 METHODS

This section describes the construction design, study design, and field and analytical methods for this testing program.

3.1 Construction Design

The topography of the SLRR bottom was surveyed in 2016. Figures 3 through 6 show contoured elevations of the river bottom, based on the 2016 data, within the project reach as well as a profiles of the river bottom along the river alignment. These figures also show the limits of construction.

The sediment removal process will consist of the three steps as follows:

1. Clear all surficial vegetation by mowing or other means. This surficial vegetation will be hauled away to the EL Corazon composting facility, where it will be composted. Surface vegetation will be carefully gathered with heavy equipment, such as truck mounted rakes, etc., such that the surface vegetation is removed and the only sediment and roots left behind.

2. Roots remaining after clearing will be grubbed to a minimum depth of 8 inches. Roots removed will also be sent to El Corazon and composted there. Grubbing will occur carefully with use of long tooth excavators and other equipment, such that the roots are pulled out and sediment left behind. Roots will be gathered on site and loaded into truck and sent to composting facility.

3. Removal of sediment will occur after clearing and grubbing and will consist of excavating by conventional heavy equipment, such as scrapers, bulldozers, front end loaders, etc. Sediment will be loaded into trucks and transported to El Corazon property and physically unsatisfactory and satisfactory sediment will be separated into two stockpiles at El Corazon. One stockpile for sand (satisfactory sediment) and the other for fines or unsatisfactory sediment.

Once the excavation and stockpiling are complete, USACE will haul the material to the beach nourishment sites and spread it on the beaches.

3.2 Sampling and Testing Design

The sampling and testing design for this Sampling and Analysis Plan Report (SAPR) covers data collection tasks for SLRR sediment collection and testing and of background soils on private property where it is proposed to stockpile the excavated sediment into two separate stockpiles; one stockpile for sand and the other for sediments with finer materials. The proposed stockpile area (El Corazon Compost Facility, 3210 Oceanside Blvd, Oceanside, CA 92056) is depicted on Figures 7 and 8.

Sediment criteria and quality objectives used to evaluate the chemical results are also discussed below.

Figure 3. Final Sampling Locations and 2016 Topographic Data for Reach 120+00 to 140+00 of the San Luis Rey River.

A

Figure 4. Final Sampling Locations and 2016 Topographic Data for Reach 140+00 to 165+00 of the San Luis Rey River.

A B

Figure 5. Final Sampling Locations and 2016 Topographic Data for Reach 165+00 to 190+00 of the San Luis Rey River.

Figure 6. Final Sampling Locations and 2016 Topographic Data for Reach 190+00 to 215+00 of the San Luis Rey River.

C

Figure 7. Location of the Proposed Stockpile Area for the San Luis Rey River Excavated Sediments.

SLRR Removal Area

Stockpile General Area

Figure 8. Approximate Stockpile Areas for the San Luis Rey River Excavated Sediments.

3.2.1 Sampling and Testing Approach

In order to evaluate placement alternatives, the main approach was to sample SLRR sediments to one foot below the project elevations (1993 invert elevations), test the sediments individually from each location for grain size distribution, composite the sediments from each location by area, then subject to composite samples to chemical analyses. In order to evaluate the suitability of the SLRR sediments for potential beach nourishment, testing followed requirements and procedures detailed in the Inland Testing Manual (ITM) (USEPA/USACE, 1998) with further guidance from Los Angeles District USACE guidelines (CESPL, undated) and from the Southern California Dredged Material Management Team (SC-DMMT) draft guidelines. In order to evaluate the SLRR sediments for reuse as imported fill, sampling and testing also followed guidelines developed by the Department of Toxic Substances Control (DTSC) for the protection of human health (DTSC, 2001). In order to evaluate the SLRR sediments for placement at a permitted landfill, the sediment testing data was evaluated against Federal and State criteria for the disposal of solid and hazardous waste. Federal hazardous waste standards were developed based on the Resource Conservation and Recovery Act (RCRA) of 1976. Guidance provided in EPA SW-846 was used to evaluate the sediments against federal standards. State hazardous waste standards are derived from California Code of Regulations (CCR) Title 22, Section 66261.24.

In addition to the general screening of sediments for the objectives listed above, sediment concentrations were evaluated by USACE, Los Angeles District to see if there would be any risks to human contact after placement of the sediments in the proposed stockpile area. To do so, data quality objectives (DQOs) were assessed to determine compliance vs. non-compliance for the protection of human health. First, the SLRR sediment chemistry data was compared to background concentrations. Sediment chemistry data derived from a composite sample of the stockpile area soils were used as background concentrations for the purpose of this study. It is assumed that if no chemical constituents in the SLRR sediments exceed any background concentrations, then there will be no increased risk to human health by stockpiling the sediments at the El Corazon composite facility.

Risks to recreational users and workers at the stockpile site were further assessed by comparing those concentrations exceeding background levels to USEPA and California EPA (Cal/EPA) screening levels for the protection of human health in residential settings, as described later in Section 3.2.5. Petroleum hydrocarbon concentrations were also compared to San Francisco Bay Regional Water Quality Control Board (SFBRWQCB) screening levels for the protection of human receptors and groundwater.

3.2.2 San Luis Rey River Sample Identification, Composite Areas, Sediment Collection and Testing

Hand Auguring, as described in Section 3.3.2 (Hand Auger Sampling Methods), was carried out to collect subsurface sediment data at 98 borehole locations (site A-10 was not sampled for sediment) throughout the SLRR sediment removal project area. These 98 locations are distributed throughout the three composite areas identified on Figures 3 through 6 as areas A, B and C. Each location was augured to a depth of one foot below the 1993 invert elevations or the elevations to which the river bottom will be restored to. This is in contrast to the information in the SAP, which states that the auger depths were to be either six or twelve feet below the ground surface. The prefix for all borehole locations was “SLRRHA16-x-##”, where x equals the composite area designation and ## equals the core designation.

The 98 locations for this study were sited during field visits to the project area that occurred during the week of June 6, 2016. Siting was based on ease of access, river bottom obstructions, and the avoidance of biologically sensitive habitats at the boring locations as well as ingress and egress to the locations. A stake with a location identifier was placed at each location and the coordinates of each location were recorded. Locations are shown on Figures 3 through 6 and the final location coordinates are provided in Tables 3 through 5. Also included in Tables 3 through 5 are the river bottom elevations at each location and the interval sampled for each location. Note that several locations were moved from the staked locations target areas with more deposition. Environmental monitoring and constraints for the sampling effort are provided in Section 3.3.3.

Separate composite samples were created from sediments within each of the three composite areas shown on Figures 3 through 6 and analyzed for bulk sediment chemistry. One composite sample was created from each composite area. Continuous samples from the river bottom to project depths or depth of refusal was collected from all boring locations. These primary borehole intervals were homogenized and formed into archive samples for potential future analyses. In addition, a length-weighted proportional subsample of each primary borehole sample was combined with all similarly weighted primary borehole intervals in a composite area to form the composite samples for chemical analyses. All archive samples are being stored frozen at Kinnetic Laboratories for at least six months unless directed otherwise by the USACE Technical Manager.

Borehole subsamples for geotechnical testing were also formed from discrete interval(s) in the primary boreholes. These samples represent varying geo-physical changes in the boring.

Surface background soil samples were also collected at eleven randomized locations within the two proposed stockpile locations. Six locations were sampled from the sand stockpile location and five locations were sampled form the fines stockpile location. Final locations of the stockpile boreholes are provided in Table 6. Samples 12-inches in depth were collected at each location using a pre-cleaned shovel. As with the SLRR boreholes, individual samples were formed and archived from each background (stockpile) area location. An equally weighted subsample of material from each background borehole were combined to form a single composite sample for chemical analyses. The prefix for all background borehole samples/locations was “SPAHA16-##.”

Table 3. Final Sampling Locations, 2016 River Bottom Elevations, and Sampling Depths for San Luis Rey River Flood Control Project Composite Area A.

Core Designation

Geographic Coordinates

(NAD 83)

California Lambert Zone 6

(NAD 83)

River Bottom Elevation1

(feet NAVD 88)

1993 Invert Elevation

(feet NAVD 88)

Core Interval Sampled

(feet NAVD 88) Date Time Latitude North

Longitude West Northing Easting

SLRRHA16-A-1 6/29/2016 10:00 33.216698º 117.361165º 2024283.5 6221835.2 24 15.1 24 – 14.1 SLRRHA16-A-2 6/29/2016 11:05 33.217139º 117.360967º 2024443.3 6221897.3 24 15.3 24 – 14.3 SLRRHA16-A-3 6/29/2016 9:43 33.217056º 117.360766º 2024412.7 6221958.5 24 15.3 24 – 14.3 SLRRHA16-A-4 6/29/2016 9:25 33.217363º 117.360524º 2024523.7 6222033.7 24 15.4 24 – 14.4 SLRRHA16-A-5 6/29/2016 11:23 33.217731º 117.360758º 2024658.0 6221963.7 24 15.5 24 – 14.5 SLRRHA16-A-6 6/29/2016 8:53 33.217649º 117.360276º 2024626.9 6222110.8 22 15.5 22 – 14.5 SLRRHA16-A-7 6/29/2016 8:32 33.217933º 117.360439º 2024730.8 6222061.8 24 15.6 24 – 14.6 SLRRHA16-A-8 6/29/2016 8:17 33.218136º 117.360671º 2024805.2 6221991.8 24 15.6 24 – 14.6 SLRRHA16-A-9 6/28/2016 14:30 33.218292º 117.359993º 2024790.7 6222218.0 18.2 15.7 18.2 – 14.7 SLRRHA16-A-11 6/28/2016 14:03 33.218547º 117.359331º 2024932.1 6222357.5 19 16.0 19 - 15.0 SLRRHA16-A-12 6/28/2016 13:10 33.218743º 117.359297º 2025021.5 6222414.4 18 16.3 18 – 15.3 SLRRHA16-A-13 6/28/2016 11:40 33.219299º 117.358406º 2025221.1 6222688.8 20 16.8 20 – 15.8 SLRRHA16-A-14 6/28/2016 13:33 33.219006º 117.359130º 2025116.9 6222466.5 18 16.5 18 – 15.5 SLRRHA16-A-15 6/28/2016 12:58 33.219025º 117.358810º 2025122.6 6222564.4 20 16.6 20 – 15.6 SLRRHA16-A-16 6/28/2016 11:30 33.219926º 117.357594º 2025446.7 6222939.8 18 17.1 18 – 16.1 SLRRHA16-A-17 6/28/2016 11:16 33.220283º 117.358440º 20255816 6222690.0 18 17.3 18 – 16.3 SLRRHA16-A-18 6/28/2016 10:55 33.220290º 117.358416º 2025581.5 6222689.6 20 17.5 20 – 16.5 SLRRHA16-A-19 6/28/2016 10:40 33.220439º 117.357174º 2025631.7 6223070.2 20 17.9 20 – 16.9 SLRRHA16-A-20 6/28/2016 10:10 33.220485º 117.356860º 2025647.4 6223166.4 20 18 20 – 17.0 SLRRHA16-A-21 6/28/2016 9:45 33.220573º 117.356364º 2025677.8 6223318.4 20 18.3 20 – 17.3 SLRRHA16-A-22 6/28/2016 9:56 33.220765º 117.356373º 2025748.0 6223316.4 22 18.4 22 – 17.4 SLRRHA16-A-23 6/28/2016 9:26 33.220655º 117.355852º 2025706.2 6223475.3 24 18.6 24 – 19.0* SLRRHA16-A-24 6/28/2016 8:19 33.221025º 117.355900º 2025840.8 6223461.9 20 18.8 20 – 17.8

Table 3. Final Sampling Locations, 2016 River Bottom Elevations, and Sampling Depths for San Luis Rey River Flood

Control Project Composite Area A (Continued).

Core Designation

Geographic Coordinates

(NAD 83)

California Lambert Zone 6

(NAD 83)

River Bottom Elevation1

(feet NAVD 88)

1993 Invert Elevation

(feet NAVD 88)

Core Interval Sampled

(feet NAVD 88) Date Time Latitude North

Longitude West Northing Easting

SLRRHA16-A-25 6/28/2016 8:52 33.220772º 117.355482º 2025747.5 6223588.7 22 18.9 22 – 17.9 SLRRHA16-A-26 6/28/2016 8:13 33.221104º 117.355359º 2025868 6223627.6 20 19 20 – 19.0 SLRRHA16-A-27 6/28/2016 8:00 33.220826º 117.354978º 2025765.3 6223743.1 22 19.2 22 – 20.0* SLRRHA16-A-28 6/28/2016 7:30 33.221239º 117.35464º 2025914.6 6223847.2 22.5 19.5 22.5 – 18.5 SLRRHA16-A-29 6/27/2016 15:20 33.221222º 117.35436º 2025907.6 6223932.2 22.7 19.7 22.7 – 18.7 SLRRHA16-A-30 6/27/2016 15:30 33.220980º 117.354116º 2025818.8 6224007.3 24 19.8 24 – 18.8 SLRRHA16-A-31 6/27/2016 14:55 33.221581º 117.353948º 2026036.8 6224061.1 23 20 23 – 19.0 SLRRHA16-A-32 6/27/2016 14:36 33.221478º 117.353525º 2025998.1 6224190.0 22 20.1 22 – 19.1 SLRRHA16-A-33 6/27/2016 14:25 33.221378º 117.353244º 2025960.7 6224275.6 22 20.2 22 – 19.0

1. River bottom elevations are based on a 2016 survey.

• Refusal Encountered

Table 4. Final Sampling Locations, 2016 River Bottom Elevations, and Sampling Depths for San Luis Rey River Flood Control Project Composite Area B.

Core Designation

Geographic Coordinates

(NAD 83)

California Lambert Zone 6

(NAD 83)

River Bottom Elevation1

(feet NAVD 88)

1993 Invert Elevation

(feet NAVD 88)

Core Interval Sampled

(feet NAVD 88) Date Time Latitude North

Longitude West Northing Easting

SLRRHA16-B-34 6/27/2016 11:55 33.221164º 117.352653º 2025881.0 6224455.4 22 20.7 22 - 19.7 SLRRHA16-B-35 6/27/2016 13:51 33.221489º 117.352760º 2025999.5 6224424.6 24 20.6 24 – 19.6 SLRRHA16-B-36 6/27/2016 11:32 33.221522º 117.351684º 2026008.1 6224753.2 22 21.1 22 – 20.2 SLRRHA16-B-37 6/27/2016 11:07 33.221709º 117.350995º 2026073.9 6224964.6 26 21.5 26 – 22.5 SLRRHA16-B-38 6/27/2016 10:41 33.220925º 117.350630º 2025787.4 6225073.2 23.8 21.8 23.8 – 20.8 SLRRHA16-B-39 6/27/2016 10:23 33.221586º 117.349557º 2026024.3 6225404.0 24 22.4 24 – 21.4 SLRRHA16-B-40 6/27/2016 10:03 33.221195º 117.348938º 2025880.3 6225591.6 24 22.6 24 – 21.6 SLRRHA16-B-41 6/27/2016 9:43 33.221788º 117.348606º 2026094.8 6225695.5 24 22.9 24 – 21.9 SLRRHA16-B-42 6/27/2016 9:09 33.221487º 117.348013º 2025983.6 6225875.5 24 23.2 24 – 22.3 SLRRHA16-B-43 6/27/2016 9:24 33.222261º 117.347636º 2026263.9 6225993.9 25.5 23.5 25.5 – 22.5 SLRRHA16-B-44 6/27/2016 8:42 33.221683º 117.346859º 2026050.9 6226229.3 26 23.8 26 – 22.8 SLRRHA16-B-45 6/24/2016 15:13 33.221814º 117.346279º 2026096.8 6226407.2 26 24.1 26 – 23.1 SLRRHA16-B-46 6/27/2016 8:20 33.222172º 117.346318º 2026227.1 6226396.5 28 24.2 28 – 23.2 SLRRHA16-B-47 6/24/2016 14:41 33.222201º 117.345623º 2026235.5 6226609.3 30 24.5 30 – 23.5 SLRRHA16-B-48 6/24/2016 14:20 33.222504º 117.345401º 2026345.0 6226678.4 32 24.7 32 – 23.7 SLRRHA16-B-49 6/24/2016 13:40 33.222672º 117.345366º 2026406.0 6226689.5 30 24.8 30 – 23.8 SLRRHA16-B-50 6/24/2016 15:33 33.223022º 117.344904º 2026531.8 6226832.2 26 25.1 26 – 24.1 SLRRHA16-B-51 6/24/2016 11:13 33.223336º 117.344470º 2026644.9 6226966.3 32 25.4 32 – 24.4 SLRRHA16-B-52 6/24/2016 10:49 33.223873º 117.345110º 2026842.24 6226772.5 30.7 25.7 30.7 – 24.7 SLRRHA16-B-53 6/24/2016 11:40 33.223953º 117.344070º 2026868.2 6227091.0 32 25.8 32 – 24.8 SLRRHA16-B-54 6/24/2016 12:57 33.224265º 117.343759º 2026980.4 6227187.2 32 26 32 – 25.0 SLRRHA16-B-55 6/24/2016 10:00 33.224838º 117.343726º 2027189.0 6227199.5 34 26.3 34 – 25.3 SLRRHA16-B-56 6/24/2016 9:45 33.225245º 117.343934º 2027337.6 6227137.5 30 26.6 30 – 25.6 SLRRHA16-B-57 6/24/2016 9:14 33.225249º 117.343428º 2027337.5 6227292.2 32 26.6 32 – 25.6

Table 4. Final Sampling Locations, 2016 River Bottom Elevations, and Sampling Depths for San Luis Rey River Flood Control Project Composite Area B (Continued).

Core Designation

Geographic Coordinates

(NAD 83)

California Lambert Zone 6

(NAD 83)

River Bottom Elevation1

(feet NAVD 88)

1993 Invert Elevation

(feet NAVD 88)

Core Interval Sampled

(feet NAVD 88) Date Time Latitude North

Longitude West Northing Easting

SLRRHA16-B-58 6/24/2016 9:34 33.225492º 117.344273º 2027428.8 6227034.5 28 26.7 28 – 25.7 SLRRHA16-B-59 6/24/2016 8:39 33.225575º 117.343551º 2027456.5 6227255.8 34 26.8 34 – 25.8 SLRRHA16-B-60 6/24/2016 8:03 33.225808º 117.344017º 2027542.7 6227114.1 30 27 30 – 26.0 SLRRHA16-B-61 6/24/2016 8:15 33.226019º 117.343722º 2027618.7 6227205.3 34 27.1 34 – 26.1 SLRRHA16-B-62 6/24/2016 7:48 33.226406º 117.344192º 2027760.9 6227062.8 30 27.4 30 – 26.4 SLRRHA16-B-63 6/23/2016 15:50 33.226602º 117.343509º 2027830.2 6227272.6 34 27.5 34 – 27.0 SLRRHA16-B-70 6/27/2016 7:55 33.222568º 117.346664º 2026393.2 6226292.5 26 24.3 26 – 23.3 SLRRHA16-B-84 6/24/2016 14:01 33.223232º 117.345608º 2026610.6 6226617.9 26 25 26 – 24.0 SLRRHA16-B-98 6/24/2016 10:31 33.224792º 117.344372º 2027174.4 6227001.7 28 26.3 28 – 25.3

*Refusal Encountered

Table 5. Final Sampling Locations, 2016 River Bottom Elevations, and Sampling Depths for San Luis Rey River Flood Control Project Composite Area C.

Core Designation

Geographic Coordinates

(NAD 83)

California Lambert Zone 6

(NAD 83)

River Bottom Elevation1

(feet NAVD 88)

1993 Invert Elevation

(feet NAVD 88)

Core Interval Sampled

(feet NAVD 88) Date Time Latitude North

Longitude West Northing Easting

SLRRHA16-C-64 6/23/2016 15:15 33.226731º 117.343892º 2027878.2 6227155.9 29.6 27.6 29.6 – 26.6 SLRRHA16-C-65 6/23/2016 15:38 33.226916º 117.343593º 2027944.3 6227248.0 30 27.7 30 – 26.7 SLRRHA16-C-66 6/23/2016 15:00 33.226958º 117.344191º 2027961.9 6227065.3 30 27.8 30 – 26.8 SLRRHA16-C-67 6/23/2016 14:38 33.227290º 117.343766º 2028081.1 6227196.4 34 28 34 – 27.0 SLRRHA16-C-68 6/23/2016 13:56 33.227426º 117.343437º 2028129.5 6227297.6 30 28.1 30 – 27.1 SLRRHA16-C-69 6/23/2016 13:12 33.227290º 117.344301º 2028083.0 6227033.1 30 28 30 – 27.0 SLRRHA16-C-71 6/23/2016 13:02 33.227576º 117.344253º 2028186.9 6227048.8 30 28.2 30 – 27.2 SLRRHA16-C-72 6/23/2016 13:30 33.227548º 117.343827º 2028175.4 6227178.9 32 28.2 32 – 27.2 SLRRHA16-C-73 6/23/2016 14:13 33.227655º 117.343554º 2028213.4 6227262.9 32 28.2 32 – 27.2 SLRRHA16-C-74 6/23/2016 12:43 33.227968º 117.344156º 2028329.2 6227079.9 30 28.4 30 – 27.4 SLRRHA16-C-75 6/23/2016 10:59 33.227994º 117.343794º 2028337.4 6227187.6 36 28.4 36 – 25.6 SLRRHA16-C-76 6/23/2016 11:58 33.228034º 117.343417º 2028350.7 6227306.1 32 28.5 32 – 27.5 SLRRHA16-C-77 6/23/2016 8:45 33.228213º 117.344333º 2028418.7 6227026.6 30 28.6 30 – 27.6 SLRRHA16-C-78 6/23/2016 9:50 33.228250º 117.343719º 2028430.2 6227214.5 34 28.6 34 – 27.6 SLRRHA16-C-79 6/23/2016 9:00 33.228525º 117.343955º 2028530.9 6227143.4 30 28.8 30 – 27.8 SLRRHA16-C-80 6/23/2016 9:20 33.228520º 117.343637º 2028528.0 6227240.6 32 28.8 32 – 27.8 SLRRHA16-C-81 6/22/2016 16:10 33.228655º 117.343362º 2028576.5 6227325.4 32 28.9 32 – 27.9 SLRRHA16-C-82 6/23/2016 8:28 33.228638º 117.344421º 2028573.7 6227001.3 30 28.9 30 – 27.9 SLRRHA16-C-83 6/23/2016 7:50 33.228822º 117.344036º 2028639.5 6227119.7 30 29.0 30 – 28.0 SLRRHA16-C-85 6/22/2016 15:51 33.228868º 117.343630º 2028654.7 6227244.3 30 29 30 – 28.0 SLRRHA16-C-86 6/22/2016 15:33 33.229100º 117.344427º 2028742.0 6227001.3 30 29.2 30 – 28.2 SLRRHA16-C-87 6/22/2016 15:14 33.229250º 117.3443215º 2028796.2 6227034.2 30 29.3 30 – 28.3 SLRRHA16-C-88 6/22/2016 14:15 33.229045º 117.343493º 2028718.8 6227286.8 32 29.2 32 - 28.2 SLRRHA16-C-89 6/22/2016 14:53 33.229239º 117.343751º 2028790.1 6227208.7 30 29.3 30 – 28.3

Table 5. Final Sampling Locations, 2016 River Bottom Elevations, and Sampling Depths for San Luis Rey River Flood Control Project Composite Area C (Continued).

Core Designation

Geographic Coordinates

(NAD 83)

California Lambert Zone 6

(NAD 83)

River Bottom Elevation1

(feet NAVD 88)

1993 Invert Elevation

(feet NAVD 88)

Core Interval Sampled

(feet NAVD 88) Date Time Latitude North

Longitude West Northing Easting

SLRRHA16-C-90 6/22/2016 10:58 33.229364º 117.343648º 2028835.5 6227240.4 36 29.4 36 – 28.4 SLRRHA16-C-91 6/22/2016 13:30 33.229355º 117.343278º 2028831.1 6227353.5 34 29.4 34 – 28.4 SLRRHA16-C-92 6/22/2016 11:31 33.229517º 117.343888º 2028892.0 6227167.8 30 29.5 30 – 28.5 SLRRHA16-C-93 6/22/2016 8:56 33.229673º 117.343328º 2028946.7 6227339.7 34 29.6 34 – 28.6 SLRRHA16-C-94 6/22/2016 16:40 33.229871º 117.344374º 2029051.3 6226634.9 33 29.7 33 – 29.7 SLRRHA16-C-95 6/22/2016 10:12 33.229986º 117.343674º 2029059.7 6227236.9 35.8 29.8 34 – 28.8 SLRRHA16-C-96 6/22/2016 9:20 33.229870º 117.343558º 2029019.1 6227269.9 36 29.8 36 – 29.5* SLRRHA16-C-97 6/22/2016 9:54 33.230303º 117.343934º 2029178.0 6227156.7 32 30 30 - 29.0 SLRRHA16-C-99 6/22/2016 8:12 33.230084º 117.343308º 2029096.4 6227347.3 36 30 36 – 29.0

*Refusal Encountered

3.2.3 Geotechnical Samples and Testing

A sufficient quantity of sediment was collected from each borehole location within the SLRR construction area and within the proposed stockpile area so that a representative amount of sediment was included in each geotechnical sample. At least one primary grain size sample was formed and analyzed from each borehole. All grain size samples collected represented the material from the river bottom elevation to one foot below the project construction elevations. All grain size samples represented layers of physically different material greater than one foot thick. Grain size analyses were also run on each primary borehole sample from the proposed stockpile area.

All mechanical grain size tests were run according to ASTM D 422 (1963). In addition to the mechanical grain size samples, four hydrometer tests were run according to ASTM D 422. The hydrometer tests were run on representative samples of fine-grained material collected from the sediment cores.

All geotechnical data gathered was used to do physical beach compatibility analyses between the SLRR sediments and a receiving beach. This task was accomplished by USACE-Los Angeles District.

Table 6. Final Sampling Locations, 2016 River Bottom Elevations, and Sampling Depths for San Luis Rey River Flood Control Project Composite Area C.

Core Designation Date Time

Geographic Coordinates

(NAD 83)

California Lambert Zone 6 (NAD 83) Core Interval

Sampled (feet bgs) Latitude

North Longitude

West Northing Easting

SPAHA16-A-1 6/30/2016 08:40 33.208977º 117.323480º 2021354 6233331 0 – 1.0

SPAHA16-A-2 6/30/2016 08:55 33.209353º 117.323104º 2021489 6233448 0 – 1.0

SPAHA16-A-3 6/30/2016 09:10 33.209170º 117.322267º 2021420 6233703 0 – 1.0

SPAHA16-A-4 6/30/2016 09:19 33.210014º 117.322520º 2021728 6233629 0 – 1.0

SPAHA16-A-5 6/30/2016 09:32 33.209449º 117.323749º 2021526 6233251 0 – 1.0

SPAHA16-A-6 6/30/2016 11:12 33.209402º 117.322571º 2021506 6233611 0 – 1.0

SPAHA16-B-1 6/30/2016 09:55 33.208543º 117.315412º 2021171 6235797 0 – 1.0

SPAHA16-B-2 6/30/2016 10:14 33.208902º 117.314682º 2021299 6236022 0 – 1.0

SPAHA16-B-3 6/30/2016 10:31 33.210332º 117.315635º 2021822 6235736 0 – 1.0

SPAHA16-B-4 6/30/2016 10:45 33.209778º 117.314986º 2021619 6235932 0 – 1.0

SPAHA16-B-5 6/30/2016 11:05 33.209286º 117.315411º 2021441 6235800 0 – 1.0

3.2.4 Summary of San Luis Rey River Testing and Evaluation Sequence

The testing and evaluation sequence for the SLRR composite samples is described in detail in the next subsection and is outlined as follows:

1) Bulk sediment chemical analyses were performed on each composite sample.

2) Grain size physical compatibility analyses was conducted by the Los Angeles District U.S.

Army Corps of Engineers Geotechnical Branch.

3) Analytical results were evaluated using the sediment quality guidelines consisting of

Effects Range Low (ERL) and Effects Range Medium (ERM) values developed by Long, et al. (1995) that correlate concentrations of selected contaminants with likelihood of adverse biological effects. The sediment chemistry summary tables in Section 4 (Results) lists available ERL and ERM values. Please note that ERLs and ERMs have not been developed for all analytes.

4) Analytical results were compared to reference/background concentrations from the proposed stockpile area and used as the DQO basis for stockpiling the sediments.

5) Analytical results were also evaluated using the USEPA’s RSL (Regional Screening Levels) (USEPA Region 9, updated 2016) and the State of California’s CHHSL (California Human Health Screening Levels) for potential effects to humans (Cal/EPA, 2005 – updated 2010). The sediment summary table in Section 4 (Results) lists the available RSL and CHHSL values. Using detected sediment concentrations for carcinogenic and RSL screening levels, the Incremental Lifetime Cancer Risk (ILCR) was calculated. Using detected sediment concentrations for non-carcinogenetic analytes and CHHSLs, Hazard Quotients (HQs) were calculated and summed into a Hazard Index (HI).

6) Analytical results were also evaluated against Toxicity Characteristic Leaching Procedure (TCLP) criteria and California Total Threshold Limit Concentrations (TTLCs). Results from the TCLP indicated that a Soluble Threshold Limit Concentrations (STLCs) was unwarranted. TTLC criteria is in the sediment results table in Section 4 (Results).

Screening values and results from the TCLP analysis are presented in Section 4.

3.2.5 Evaluation Guidelines

As mentioned above, to aid in the evaluation of sediment test data, chemical concentrations of contaminants found within the sediments were compared to sediment quality guidelines (Long et.

al., 1995) developed by NOAA. These guidelines were used to screen sediments for contaminant concentrations that might cause adverse biological effects and to identify sediments for further toxicity testing. For any given contaminant, ERL guidelines represent the 10th percentile concentration value in the NOAA database that might be expected to cause adverse biological effects and ERM guidelines reflect the 50th percentile value in the database. Note that ERLs and ERMs will only be used as a screening tool. They were not used to determine suitability.

As an additional measure of potential toxicity, the mean ERM quotient (ERMq) for the composite sample were calculated according to Long et al. (1998a) and Hyland et al. (1999). ERMq is calculated by dividing each contaminant concentration by its respective ERM value and then summing the results and dividing through by the number of contaminants as shown in the following equation:

∑= ERM

entrationSampleConctERMQuotien 24

In cases where concentrations of measured contaminants are below the method detection limit (MDL), a value of ½ the MDL was used for the ERMq calculations. For a general overall indication of toxicity, a quotient less than 0.1 is indicative of a low probability (<12%) of a highly toxic response to marine amphipods (Long and MacDonald, 1998b). If there are no ERL exceedances in a sample, there is less than a 10% probability of a highly toxic response to marine amphipods. The probability of a highly toxic response increases to 71% for quotients greater than 1.0.

The river bottom material was also evaluated as to whether or not it is suitable for human contact.

This was done to determine suitability for reuse of the material for beach nourishment and clean imported fill and to further assess chemical constituents that exceed background levels at the proposed stockpile area. To do so, the chemical results were compared to “Regional Screening Levels for Chemical Contaminants at Superfund Sites" (USEPA Region 9, updated May 2016), formerly known as Preliminary Remediation Goals (PRGs). These screening levels (RSLs) were developed for Superfund/RCRA programs and are a consortium of USEPA Region 9 Preliminary Remediation Goals (PRGs), USEPA Region 3 Risked-Based Concentrations (RBCs) and EPA Region 6 Human Health Medium – Specific Screening Levels (HHMSSLs). RSLs are risk-based concentrations derived from standardized equations combining exposure information assumptions with EPA toxicity data. RSLs used in this report are based on a conservative target hazard quotient of 0.1. In addition, all the carcinogenic risk estimates for detected analytes were summed to determine the Incremental Lifetime Cancer Risk.

RSLs are considered by the USEPA to be protective for humans (including sensitive groups) over a lifetime. However, RSLs are not always applicable to a particular site and do not address non-human health endpoints, such as ecological impacts. The RSLs in the sediment chemistry summary table were calculated without site-specific information. They are used for site "screening." RSLs are not cleanup standards and were not applied as such. The RSL's primary role in site "screening" is to help identify areas, constituents, and conditions that require further federal attention at a particular site, and is also useful in determining risks to human exposure at non-superfund sites. RSLs may be lower than the California Title 22 Total Threshold Limit Concentration (TTLC) values, but often are much higher.

Human health risks were also evaluated using California Human Health screening Levels (CHHSLs). CHHSLs (Cal/EPA, updated 2010) are concentrations of 54 hazardous chemicals in soil or soil gas that are considered to be protective of human health. The CHHSLs were developed by the Office of Environmental Health Hazard Assessment (OEHHA) on behalf of California Environmental Protection Agency (Cal/EPA). CHHSLs were developed using standard exposure assumptions and chemical toxicity values published by the USEPA and Cal/EPA. CHHSLs listed in in the sediment chemistry table (Section 4) were developed separately for industrial/commercial settings and for residential settings. In addition, Hazard Quotients (HQs) for detected non-carcinogenic analytes were summed to derive a Hazard Index (HI) to estimate cumulative risks.

If the SLRR excavated material is to be placed at a permitted California Class III solid waste landfill, then the river bottom sediments need to be evaluated to determine if they are non-hazardous. Specific analyses and criteria adopted in California Code of Regulations (CCR) Title 22, Section 66261.24, 40 CFR parts 247 & 248 (Subtitle D), the San Diego Regional Water Quality Control Board (SDRWQCB) Order No. 93-86, and the San Diego County Sanitation District Soil Acceptance Program were used to evaluate the sediments. First, the solids results were evaluated against TTLCs, TCLPs and concentration limits established in SDRWQCB Order No. 93-86.

Petroleum hydrocarbon specific limits are provided in Order No. 93-86 and the County Sanitation District Soil Acceptance Program. Otherwise, these documents specify that solid wastes must comply with State and Federal provisions. Generally, sediments with concentrations of Title 22 soluble contaminants that are less than 10% of the TTLC are usually considered non-hazardous.

Title 22 soluble contaminants are those contaminants with corresponding Title 22 STLC regulatory levels. No contaminant was present in a concertation greater than 10% of the TTLC, then Title 22 Waste Extraction Test (WET) procedures would have been conducted, however no contaminant was present at or greater than 10% of the TTLC and so no WET testing was required.

Limits for petroleum hydrocarbons are specified in the County Sanitation District Soil Acceptance Program and are provided in sediment chemistry results (Section 4). Petroleum hydrocarbons were also compared to Environmental Screening Levels (ESLs) developed by the San Francisco Bay Regional Water Quality Control Board (SFBRWQCB, 2016).

Included as part of the hazardous waste assessment is a California Fish and Wildlife is a 96-hour acute fish bioassay. According to CCR Title 22 Section 66696, a sample is considered non-hazardous if it produces an LC50 of greater than 500 mg/L.

3.3 Field Sampling Protocols

Hand auger sampling, decontamination, sample processing and documentation procedures are discussed in this section.

3.3.1 Positioning and Elevation Measurements

Positioning at sampling locations will be accomplished using a mapping grade differential GPS (DGPS) or GNSS receiver with x, y and z positioning accuracies of less than one foot. Final horizontal coordinates at each location shall be recorded in both Geographic coordinates (NAD

83) and State Plane Coordinates (CA Zone VI, NAD 83). River bottom elevations in NAVD 83 datum were determined from the 2016 topographic maps.

All sampling sites were located at the locations staked during the initial environmental site evaluation and were accessed according to the conditions presented in Section 3.3.3. If rejection was encountered at the staked location, one additional attempt was made within 10 feet of the staked location.

3.3.2 Hand Auger Sampling Methods

All sediment samples were collected using a three-inch diameter stainless steel hand auger. All boreholes were advanced to the 1993 invert elevations plus one foot or to refusal. The depth of refusal is defined as the depth at which the hand auger cannot be advanced into the soil or caving of the hole. At sites where the depth of refusal was reached prior to the sample depth, one additional attempt was made to reach the sample depth. If the sample depth could not be reached after the additional attempt, the deeper of the two borehole samples was retained for testing. Individual borehole sample processing took place on site. Composite sample formation took place at Kinnetic Laboratories’ facility in Carlsbad, CA.

Regardless of the auger type used, hand auguring does not produce a continuous core. The device was advanced only a set distance at a time.