October 31, 2019 Via E-Mail Sean Sheldrake U.S. ...

October 31, 2019 Via E-Mail Sean Sheldrake U.S. Environmental Protection Agency 1200 Sixth Avenue, Suite 900 M/S ECL-115 Seattle, WA 98101 [email protected] Re: River Mile 11E Final Basis of Design Report

Portland Harbor Superfund Site (PHSS) Dear Mr. Sheldrake: Enclosed is the final Basis of Design Report (BODR) for the River Mile 11E (RM11E) Project Area prepared in response to EPA’s September 17, 2019 conditional approval letter. The final BODR includes the changes that were detailed on our June 27, 2019 response to EPA comments on the draft BODR. Also enclosed is a redline version of the final BODR showing the changes made to the draft BODR along with the associated numbered comment response indicating the basis of the change.

The BODR was prepared by Dalton, Olmsted & Fuglevand, Inc. (DOF) and GSI on behalf of Cargill, Inc.; CBS Corporation; City of Portland; DIL Trust; Glacier Northwest, Inc.; and PacifiCorp. The report was prepared in accordance with the BODR Work Plan as approved by EPA on May 31, 2018, and the Amended Administrative Settlement Agreement and Order on Consent (ASAOC) between the RM11E Group and the U.S. Environmental Protection Agency, CERCLA Docket No. 10-2013- 0087 (effective April 15, 2013; amended January 11, 2018).

Your September 17, 2019 letter included four specific items that we will address during remedial design (RD) as follows:

1. River Bank Characterization. The RM11E Group’s AOC and studies to date include riverbanks in the RM11E Project Area. The completed RM11E Recontamination Assessment Report dated November 2018 and the BODR address many of the assessments of riverbank chemical and physical characteristics, erodibility and stability, as called for in EPA’s Guidance for River Bank Characterizations and Evaluation at the Portland Harbor Superfund Site (RBCE). A forthcoming RD sampling and analysis program will describe a supplemental investigation that includes the riverbank characterization for EPA’s review and approval. The RM11E Remedial Design Work Plan (RDWP) will continue to address the application of RBCE at the RM11E Project Area in ongoing RD work, such as riverbank habitat characteristics and bank stabilization measures consistent with the Portland Harbor Superfund Site Record of Decision.

Basis of Design Report River Mile 11 East

Prepared for

RM11E Group October 2019

Prepared by

Dalton, Olmsted & Fuglevand, Inc.

and GSI Water Solutions, Inc.

With

David Evans and Associates, Inc. Geotechnical Resources, Inc.

Grette Associates LLC KPFF Consulting Engineers

Mott MacDonald

Basis of Design Report

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Contents 1. Introduction ...................................................................................................................... 1

1.1 General .................................................................................................................. 1 1.2 Project Mile Baseline ........................................................................................... 3 1.3 Project Datum ...................................................................................................... 3 1.4 Report Organization ........................................................................................... 4

2. Site Conditions ................................................................................................................ 5 2.1 RM11E Project Area ............................................................................................ 5 2.2 RM11E Upland Area and Source Control Status ............................................ 5 2.3 Shoreline Ownership and Operations .............................................................. 7 2.4 Physical Site Setting ............................................................................................ 9

2.4.1 Regional Geologic and Seismic Setting ................................................ 9 2.4.2 Local Geologic Setting .......................................................................... 10 2.4.3 Physical Sediment Data ........................................................................ 12 2.4.4 Local Hydrogeologic Setting ................................................................ 14 2.4.5 Climate Change and Flood Rise Considerations .............................. 15

2.5 Implementability Site Factors .......................................................................... 16 2.5.1 Facility Operations ................................................................................ 17 2.5.2 Navigation Clearance ............................................................................ 17 2.5.3 Construction Access .............................................................................. 18 2.5.4 Submarine Cable Crossings ................................................................. 18 2.5.5 Groups of Vertical Pile Remnants ....................................................... 18 2.5.6 Large Undifferentiated Debris ............................................................. 19 2.5.7 Oversteepened Slopes ........................................................................... 19 2.5.8 Structure Stability and Capacity .......................................................... 19 2.5.9 Vessel Propeller Wash .......................................................................... 20 2.5.10 Wave Action ........................................................................................... 20

2.6 Remediation Thresholds (RTs) ........................................................................ 20 2.7 Nature and Extent of Focused COCs .............................................................. 21

2.7.1 Surface Sediment and Sediment Management Areas ...................... 21 2.7.2 Riverbank and Top-of-Bank Surface Soil ........................................... 22 2.7.3 Subsurface Sediment ............................................................................. 23 2.7.4 Total PCB Depth of Impact Evaluation .............................................. 24 2.7.5 Upland Subsurface Soil......................................................................... 25 2.7.6 Groundwater .......................................................................................... 25 2.7.7 Porewater ................................................................................................ 25 2.7.8 Surface Water ......................................................................................... 26

2.8 Recontamination Assessment Summary ........................................................ 26 2.8.1 Upland Pathway Conclusions ............................................................. 27 2.8.2 In-Water Pathway Conclusions ........................................................... 28 2.8.3 Recontamination Considerations for Design ..................................... 30

2.9 Site-Specific CSM Refinements for RD ........................................................... 31 3. Design Criteria ............................................................................................................... 33

3.1 Remediation Technologies (ROD 10.1.1) ........................................................ 33 3.1.1 Containment ........................................................................................... 33 3.1.2 In Situ Treatment ................................................................................... 34 3.1.3 Removal .................................................................................................. 34


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3.1.4 Disposal at Offsite Commercial Landfills .......................................... 34 3.1.5 Ex Situ Treatment .................................................................................. 34 3.1.6 Enhanced Natural Recovery ................................................................ 34 3.1.7 Monitored Natural Recovery ............................................................... 35

3.2 River Regions (ROD 14.2) ................................................................................. 35 3.3 Institutional Controls (ROD 14.2.6) ................................................................ 38 3.4 Design Requirements (ROD 14.2.9) ................................................................ 38

3.4.1 Capping Design (ROD 14.2.9.1) ........................................................... 38 3.4.2 Dredging Design (ROD 14.2.9.2) ......................................................... 40 3.4.3 In Situ Treatment Design (ROD 14.2.9.3) ........................................... 41 3.4.4 Enhanced Natural Recovery Design (ROD 14.2.9.4) ........................ 41 3.4.5 Riverbanks (ROD 14.2.9.5) ................................................................... 42

3.5 RA Performance Standards (ROD 14.2.10) .................................................... 42 3.6 Key ARARs (ROD 10.1.1.10) ............................................................................ 42

3.6.1 Waste Designation ................................................................................. 42 3.6.2 Section 10 of the Rivers and Harbors Act .......................................... 42 3.6.3 Section 404 of the CWA ........................................................................ 43 3.6.4 Section 401 of the CWA ........................................................................ 43 3.6.5 Endangered Species Act ....................................................................... 43 3.6.6 FEMA Floodplain Regulations ............................................................ 43 3.6.7 Standards for Surface Water and Groundwater ............................... 43

3.7 Seismic Considerations ..................................................................................... 45 3.7.1 Code-Based Seismic Design Considerations ..................................... 45 3.7.2 Preliminary Liquefaction and Lateral Spreading Assessment ........ 45

3.8 Zoning and Future Land Use ........................................................................... 46 3.9 Easement and Access Requirements............................................................... 47

4. Remedial Technology Screening ................................................................................ 49 4.1 ROD Technology Assignments ....................................................................... 49 4.2 RM11E Site Factors ............................................................................................ 49 4.3 Remediation Technology Screening ............................................................... 49

4.3.1 Oversteepened Slopes ........................................................................... 50 4.3.2 Facility Operations ................................................................................ 50 4.3.3 Submarine Cable Crossing ................................................................... 51 4.3.4 Groups of Vertical Pile Remnants ....................................................... 51 4.3.5 Large Undifferentiated Debris ............................................................. 52 4.3.6 Representative Project Cross Sections ................................................ 52

4.4 Conclusion .......................................................................................................... 52 5. Remedial Technology Evaluation .............................................................................. 53

5.1 Step 1: Cross Sections ........................................................................................ 53 5.1.1 Cross Section Features .......................................................................... 54 5.1.2 ROD Technology vs. Site Factors ........................................................ 56

5.2 Step 2: Facility Characteristics ......................................................................... 58 5.2.1 Development Plans ............................................................................... 59 5.2.2 Access ...................................................................................................... 60 5.2.3 Operations .............................................................................................. 60 5.2.4 Upland Bank Stabilization ................................................................... 63


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5.2.5 Schedule .................................................................................................. 64 5.2.6 Integration .............................................................................................. 65 5.2.7 Other RM11E Facilities ......................................................................... 67 5.2.8 Technology Attributes Compatible with Facility Factors ................ 67

5.3 Step 3: Physical Compatibility ......................................................................... 68 5.3.1 Sediment ................................................................................................. 68 5.3.2 Slopes ...................................................................................................... 70 5.3.3 Riverbanks .............................................................................................. 73 5.3.4 Structures/Utilities ............................................................................... 74 5.3.5 Debris ...................................................................................................... 76 5.3.6 Technology Attributes Compatible with Physical Characteristics . 77

6. Site-Specific Remedial Approach .............................................................................. 79 6.1 Step 4: Compatible Technologies .................................................................... 79

6.1.1 Northern SMA Offshore of Sakrete (PM 10.92) ................................. 80 6.1.2 RIS&G Barge Berth (PM 11.14) ............................................................ 80 6.1.3 ODOT Outfall WR-306 (PM 11.15) ...................................................... 81 6.1.4 Glacier NW Barge Dock (PM 11.19) .................................................... 82 6.1.5 Glacier NW Open Slope (PM 11.24) .................................................... 83 6.1.6 Glacier NW Main Dock (PM 11.31) ..................................................... 84 6.1.7 PacifiCorp Submarine Cable Crossing (PM 11.36) ........................... 86 6.1.8 Cargill Former Crane Tramway, Outfall OF43 (PM 11.39) .............. 87 6.1.9 Cargill Main Dock (PM 11.46) ............................................................. 90 6.1.10 Summary of Technologies .................................................................... 93

6.2 Step 5: Effectiveness .......................................................................................... 93 6.2.1 Porewater Management ....................................................................... 94 6.2.2 Erosion Control ...................................................................................... 94 6.2.3 Zero Flood Rise and Navigation ......................................................... 94 6.2.4 Limiting Environmental Exposure During Dredging ...................... 96 6.2.5 In-Water Work Windows/Habitat ..................................................... 99 6.2.6 Water Quality Controls....................................................................... 100 6.2.7 Materials Disposal ............................................................................... 102 6.2.8 Sediment Transload and Transport .................................................. 105 6.2.9 Source Materials .................................................................................. 109 6.2.10 Green Remediation .............................................................................. 110

6.3 Step 6: Consistency with the ROD ................................................................ 110 7. Performance Standards and Monitoring ................................................................. 113

7.1 RA Performance Standards and Monitoring ............................................... 113 7.1.1 Water Quality During RA .................................................................. 113 7.1.2 Dredging and Close Out ..................................................................... 114 7.1.3 Residual Management Cover ............................................................ 116 7.1.4 Capping ................................................................................................. 117

7.2 Baseline and Long-Term Monitoring ........................................................... 118 7.2.1 Baseline SWAC .................................................................................... 118 7.2.2 Caps ....................................................................................................... 118 7.2.3 Habitat Mitigation Areas .................................................................... 119

8. Design Studies ............................................................................................................. 121 8.1 RD Sediment Characterization ...................................................................... 121


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8.1.1 Phase 1 RD Sediment Characterization ............................................ 121 8.1.2 Phase 2 RD Sediment Characterization ............................................ 122

8.2 RD Technical Studies and Alternatives Evaluation .................................... 122 8.2.1 Compatible Remediation Technologies ........................................... 123 8.2.2 Facility Access and Modification Options for RA .......................... 124 8.2.3 Technical Studies for Alternatives Evaluation and RD .................. 127 8.2.4 Preferred Alternative Report ............................................................. 130

8.3 Additional RD Investigations ........................................................................ 130 9. Remedial Design Sequencing ................................................................................... 133

9.1 Remedial Design Work Plan .......................................................................... 133 9.2 30% Design ....................................................................................................... 133 9.3 60% - 95% - 100% Design ................................................................................ 134

10. References ..................................................................................................................... 137

Tables Table 1-1 RM11E Elevation-Related Criteria Table 2-1 Source Control Sufficiency Assessment Summary Matrix Table 2-2 Sediment and Soil Grain Size, Organic Carbon, and Total Solids Data Table 2-3 Visual Sediment and Soil Sample Observations Table 2-4 Geotechnical Parameters in Surface and Subsurface Sediment Samples Table 2-5 Remediation Thresholds Table 2-6 Focused COC Concentrations in Surface Sediment and Soil Table 2-7 Focused COC Concentrations in Subsurface Sediment and Soil Table 2-8 Total PCB Depth of Impact in Sediment and Soil Table 2-9 Focused COC Concentrations in Groundwater Table 2-10 Estimated Total PCB Concentrations in Porewater Table 2-11a Estimated Total PCB Concentrations in Surface Water (RM11E

Supplemental RI/FS Results) Table 2-11b Focused COC Concentrations in Surface Water (PHSS Round 3 RI Results) Figures Figure 1-1 Vicinity Map Figure 1-2 Project Mile (PM) Versus USACE Navigation Channel Stationing (RM) Figure 1-3 NAVD88 Datum vs CRD Datum Figure 2-1 RM11E Base Map Figure 2-2 Schematic of Willamette River Sampling Areas, Elevations, and Media Figure 2-3 RM11E Upland Drainage Area and Cleanup Sites Figure 2-4 Tectonic Setting Summary Figure 2-5 Local Fault Map Figure 2-6a Conceptual Riverbed Lithology and Cross Section Overview Figure 2-6b Conceptual Geologic Cross Sections A-A’ – Perpendicular to Bank Figure 2-6c Conceptual Geologic Cross Sections B-B’ – Parallel to Bank Figure 2-7a-b Grain Size Distribution – Surface Sediment Figure 2-8a-b Grain Size Distribution – Subsurface Sediment Figure 2-9 Visual Sediment and Soil Observations of Predominant Grain Size


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Figure 2-10 Predicted Range of 10/50/90 Percentile Flows at Willamette Falls Figure 2-11 Waterfront Facilities Figure 2-12 Waterfront Use High-Impact Ranked Areas Figure 2-13a Debris High-Impact Ranked Areas Figure 2-13b Debris and Shoreline Structure Site Plan, PM 11.35 to PM 11.54 Figure 2-13c Groups of Vertical Piles, 3D Detail Example Figure 2-14 Geotechnical High-Impact Ranked Areas Figure 2-15 Hydrodynamics High-Impact Ranked Areas Figure 2-16a-e RM11E Sediment and Soil Sample Locations Figure 2-17 Total PCBs in Sediment and Soil Figure 2-18 Total PAH in Sediment and Soil Figure 2-19 Total DDx in Sediment and Soil Figure 2-20 PeCDD in Sediment and Soil Figure 2-21 PeCDF in Sediment and Soil Figure 2-22 TCDD in Sediment and Soil Figure 2-23 RM11E Sediment Management Areas Figure 2-24 Total PCB Depth of Impact Figure 2-25 RM11E Groundwater, Porewater, and Surface Water Sample Locations Figure 2-26 Recontamination Pathways Conceptual Site Model Figure 2-27 Tarr Groundwater Remedial Action Area and PCE/TCE Plume Extent Figure 2-28a Human Health Risk Assessment Conceptual Site Model for the PHSS Figure 2-28b Major Elements of the PHSS Conceptual Site Model Figure 2-28c Physical Conceptual Site Model for the PHSS Figure 2-28d Baseline Ecological Risk Assessment (BERA) Conceptual Site Model for the

PHSS Figure 2-29 Design CSM Components Figure 3-1 ROD Technology Assignment by River Region Figure 3-2 Technology Application Decision Tree Figure 3-3 City of Portland Zoning Map No. 2829 Figure 4-1 ROD Technology Assignments Figure 4-2 SMA Technology Assignments by RM11E River Region Figure 4-3 Remedial Technology Screening/ Site Factors vs. ROD Technologies Figure 5-1a Cross Section Overview Figures Figure 5-1b Cross Section PM 10.92. Sakrete Figure 5-1c Cross Section PM 11.02. Stan Herman Figure 5-1d Cross Section PM 11.12. RIS&G Barge Berth Figure 5-1e Cross Section PM 11.15. ODOT Outfall WR-306 Adjacent to RIS&G Figure 5-1f Cross Section PM 11.19. Glacier NW Barge Dock Figure 5-1g Cross Section PM 11.24. Open Slope at Glacier NW Figure 5-1h Cross Section PM 11.31. Southern End of Glacier NW Main Dock Figure 5-1i Cross Section PM 11.36. Open Slope at PacifiCorp Cable Crossing Figure 5-1j Cross Section PM 11.39. Former Crane Tramway and City Outfall OF43 Figure 5-1k Cross Section PM 11.46. Mid-Length of Cargill Main Dock


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Figure 5-2a Technology Screening Cross Section PM 10.92. Sakrete Figure 5-2b Technology Screening Cross Section PM 11.14. RIS&G Barge Berth Figure 5-2c Technology Screening Cross Section PM 11.15. ODOT Outfall WR-306 Figure 5-2d Technology Screening Cross Section PM 11.19. Glacier NW Barge Dock Figure 5-2e Technology Screening Cross Section PM 11.24. Open Slope at Glacier NW Figure 5-2f Technology Screening Cross Section PM 11.31. Southern End of Glacier NW

Main Dock Figure 5-2g Technology Screening Cross Section PM 11.36. Open Slope at PacifiCorp

Cable Crossing Figure 5-2h Technology Screening Cross Section PM 11.39. Former Crane Tramway and

City Outfall OF43 Figure 5-2i Technology Screening Cross Section PM 11.46. Mid-Length of Cargill Main

Dock Figure 5-3a Toe Buttress Concept Cross Section Figure 5-3b Toe Wall Concept Cross Section Figure 6-1 Dredging Concept Cross Section PM 10.92. Sakrete Figure 6-2 Dredging Concept Cross Section PM 11.14. RIS&G Barge Berth Figure 6-3 Dredging Concept Cross Section PM 11.15. ODOT Outfall WR-306 Figure 6-4a Toe Wall & Cap Concept Cross Section PM 11.19. Glacier NW Barge Dock Figure 6-4b Dredging Concept Cross Section PM 11.19. Glacier NW Barge Dock Figure 6-5 Dredging Concept Cross Section PM 11.24. Open Slope at Glacier NW Figure 6-6a Toe Wall & Cap Concept Cross Section PM 11.31. Southern End of Glacier

NW Main Dock Figure 6-6b Dredging Concept Cross Section PM 11.31. Southern End of Glacier NW

Main Dock Figure 6-6c ACB Mat Cap/Dredging Concept Cross Section PM 11.31 Southern End of

Glacier NW Main Dock Figure 6-7a Dredging Concept Cross Section PM 11.36. Open Slope at PacifiCorp Cable

Crossing Figure 6-7b Engineered Cap & Dredging Concept Cross Section PM 11.36. Open Slope

at PacifiCorp Cable Crossing Figure 6-8a Toe Wall & Cap Concept Cross Section PM 11.39. Former Crane Tramway

and City Outfall OF43 Figure 6-8b Diver Dredging Concept Cross Section PM 11.39. Former Crane Tramway

and City Outfall OF43 Figure 6-8c ACB Mat Cap/Dredging Concept Cross Section PM 11.39. Former Crane

Tramway and City Outfall OF43 Figure 6-8d Remnant Piling Cap/Dredging Concept Cross Section PM 11.39. Former

Crane Tramway and City Outfall OF43 Figure 6-8e Bank Layback and Dredging Concept Cross Section PM 11.39. Former

Crane Tramway and City Outfall OF43 Figure 6-9a Toe Wall & Cap Concept Cross Section PM 11.46. Mid-Length of Cargill

Main Dock Figure 6-9b Diver Dredging Concept Cross Section PM 11.46. Mid-Length of Cargill

Main Dock


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Figure 6-9c ACB Mat Cap/Dredging Concept Cross Section PM 11.46. Mid-Length of Cargill Main Dock

Figure 6-9d Remnant Piling Cap/Dredging Concept Cross Section PM 11.46. Mid-Length of Cargill Main Dock

Figure 6-9e AquaGate®/Dredging Concept Cross Section PM 11.46. Mid-Length of Cargill Main Dock

Figure 6-9f Full Bank Layback and Dredge Concept Cross Section PM 11.46. Mid-Length of Cargill Main Dock

Figure 8-1 Compatible Remediation Technologies Figure 9-1 30% Design Sequence Exhibits Exhibit 2-1 Summary of Visual Sediment Classifications ............................................ 13 Exhibit 2-2 Summary of Potential Timing Impacts on Remedial Alternatives ......... 17 Exhibit 2-3 Sampling Areas, Elevations, and Media Terminology ............................. 21 Exhibit 6-1 ROD Technology Assignment by River Region, PM 10.92 ...................... 80 Exhibit 6-2 ROD Technology Assignment by River Region, PM 11.14 ...................... 80 Exhibit 6-3 ROD Technology Assignment by River Region, PM 11.15 ...................... 81 Exhibit 6-4 ROD Technology Assignment by River Region, PM 11.19 ...................... 82 Exhibit 6-5 ROD Technology Assignment by River Region, PM 11.24 ...................... 83 Exhibit 6-6 ROD Technology Assignment by River Region, PM 11.31 ...................... 84 Exhibit 6-7 ROD Technology Assignment by River Region, PM 11.36 ...................... 86 Exhibit 6-8 ROD Technology Assignment by River Region, PM 11.39 ...................... 87 Exhibit 6-9 ROD Technology Assignment by River Region, PM 11.46 ...................... 90 Appendices Appendix A RM11E Facility Factors Appendix B RM11E Facility Characteristics Interviews (2018) Appendix C Work Timing Analysis


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Acronyms and Abbreviations

ug/kg microgram per kilogram

ACB articulated concrete block

AOC Administrative Settlement Agreement and Order on Consent

ARAR applicable or relevant appropriate requirement

ASCE American Society of Civil Engineers

BA biological assessment

BEHP bis(2-ethylhexyl)phthalate

BFE Base Flood Elevation

bgs below ground surface

bml below mudline

BMP best management practice

BODR Basis of Design Report

BODR Work Plan Basis of Design Report Work Plan

Cargill Cargill, Inc.

CBS CBS Corporation

CERCLA Comprehensive Environmental Response Compensation and Liability Act

CFR Code of Federal Regulations

City City of Portland

CLE contingency-level earthquake

cm centimeter

COC contaminant of concern

CRD Columbia River Datum

CSM conceptual site model

CSO combined sewer overflow

CSZ Cascadia Subduction Zone

CUL cleanup level

CWA Clean Water Act

DDD dichlorodiphenyldichloroethane

DDE dichlorodiphenyldichloroethylene

DDT dichlorodiphenyltrichloroethane

DDx sum of DDD, DDE, and DDT

DEA David Evans and Associates, Inc.

DEQ Oregon Department of Environmental Quality

DoC depth of contamination

DOF Dalton, Olmsted & Fuglevand, Inc.


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DOI depth of impact

DoS Declaration of Security

DSL Oregon Department of State Lands

DTM digital terrain model

dw dry weight

EFH Essential Fish Habitat

ENR enhanced natural recovery

EPA U.S. Environmental Protection Agency

ESA Endangered Species Act

FEMA Federal Emergency Management Agency

FIS Flood Insurance Study

FMD future maintenance dredging

ft feet

g/cm3 grams per cubic centimeter

Glacier NW Glacier Northwest, Inc.

GPS global positioning system

GRI Geotechnical Resources, Inc.

GSI GSI Water Solutions, Inc.

HDD horizontal directional drilling

HEA habitat equivalency analysis

HEC-RAS Hydrologic Engineering Center River Analysis System

HI hazard index

HOC hydrophobic organic compound

HxCDF 1,2,3,4,7,8- Hexachlorodibenzofuran

I-5 Interstate 5

I-405 Interstate 405

IC institutional control

ICIAP Institutional Controls Implementation and Assurance Plan

KPFF KPFF Consulting Engineers

kV kilovolt

LDR land disposal restriction

MCL maximum contaminant level

MCLG maximum contaminant level goal

MDL method detection limit

mg/kg milligrams per kilogram

mg/L milligrams per liter


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MGP manufactured gas plant

MIT Massachusetts Institute of Technology

MNR monitored natural recovery

MOTEM Marine Oil Terminal and Engineer and Maintenance

MOU Memorandum of Understanding

NAD83 North American Datum of 1983

NAPL nonaqueous-phase liquid

NAVD88 North American Vertical Datum of 1988

NAV U.S. Army Corps of Engineers’ Willamette River Navigation Channel NFIP National Flood Insurance Program

ng/L nanogram per liter

NMFS National Marine Fisheries Service

NOAA National Oceanic and Atmospheric Administration

NRC not reliably contained

NRWQC National Recommended Water Quality Criteria

NTU nephelometric turbidty unit

O&M operations and maintenance

OAR Oregon Administrative Rules

ODOT Oregon Department of Transportation

ODFW Oregon Department of Fish and Wildlife

OF outfall

OHW ordinary high water

OSSC Oregon Structural Specialty Code

PAC powdered activated carbon

PAH polycyclic aromatic hydrocarbon

PCB polychlorinated biphenyl

PCC Portland City Code

PCE tetrachloroethylene

PeCDD 1,2,3,7,8-pentachlorodibenzo-p-dioxin

PeCDF 2,3,4,7,8-pentachlorodibenzofuran

PHSS Portland Harbor Superfund Site

PM project mile

PTW principal threat waste

RA remedial action

RAL remedial action level

RAO remedial action objective


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RCRA Resource Conservation and Recovery Act

RD remedial design

RDM remediation dredging method

RI/FS remedial investigation/feasibility study

RIS&G Ross Island Sand & Gravel

RM River Mile

RMC residual management cover

RM11E River Mile 11 East

RM11E Group Cargill, Inc. (Cargill); CBS Corporation (CBS); City of Portland (City); DIL Trust; Glacier Northwest, Inc. (Glacier NW); and PacifiCorp

RMJOC River Management Joint Operation Committee

ROD record of decision

RPC RM11E recontamination potential chemical

RSL EPA regional screening level

RT remediation threshold

SCM source control measure

SDWA Safe Drinking Water Act

SMA sediment management area

SOW Statement of Work

Tarr Tarr, Inc.

TCDD 2,3,7,8-tetrachlorodibenzo-p-dioxin

TCE trichloroethylene

TCLP Toxicity Characteristic Leaching Procedure

TOC total organic carbon

TPH total petroleum hydrocarbon

TSCA Toxic Substance Control Act

UPRR Union Pacific Railroad

USACE U.S. Army Corps of Engineers

USFWS U.S. Fish and Wildlife Service

USGS U.S. Geological Survey

WQS Oregon Water Quality Standards

WSE water surface elevation


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1. Introduction

1.1 General This Basis of Design Report (BODR) for the River Mile 11 East (RM11E) Project Area of the Portland (Oregon) Harbor Superfund Site (PHSS) was prepared by Dalton, Olmsted & Fuglevand, Inc. (DOF), as prime consultant; with support from David Evans and Associates, Inc. (DEA), as mapping subconsultant; GSI Water Solutions, Inc. (GSI), as environmental subconsultant; Geotechnical Resources, Inc. (GRI), as geotechnical subconsultant; Grette Associates as habitat consultant, KPFF Consulting Engineers (KPFF) as structural subconsultant; and Mott MacDonald as river hydraulics subconsultant.

The BODR was prepared in accordance with the RM11E BODR Work Plan (DOF and GSI, 2018) and Section 3.2 of the Remedial Design (RD) Statement of Work (RD SOW) for the RM11E Project Area, part of Administrative Settlement Agreement and Order on Consent for Supplemental Remedial Investigation/Feasibility Study (RI/FS) Work and Remedial Design, U.S. Environmental Protection Agency (EPA) Region 10, Comprehensive Environmental Response Compensation and Liability Act (CERCLA) Docket No. 10-2013-0087 (AOC), Amendment No. 1 (Amended AOC/SOW; EPA, 2018a). The document was prepared on behalf of Cargill, Inc. (Cargill); CBS Corporation (CBS); City of Portland (City); DIL Trust; Glacier Northwest, Inc. (Glacier NW); and PacifiCorp, collectively referred to as the RM11E Group.

The RM11E Project Area lies between approximately River Mile (RM) 10.9 and RM 11.6 along the east bank of the Willamette River (Figure 1-1). The shoreline area includes numerous active waterfront structures, remnant structures, and public and private stormwater outfalls. As established in the SOW of the original AOC, the RM11E Project Area also “includes the riverbank area to the top of the bank (hereinafter identified as the Project Area). Riverbank soils will be evaluated to determine if there are recontamination concerns, design and/or remedial action implementability considerations associated with the riverbank areas” (Section 1 of SOW).

The BODR evaluates feasible remedial technologies at RM11E and identifies site-specific remedial approaches to take further into design, in conformance with the PHSS Record of Decision (ROD; EPA, 2017), the known nature and extent of impacted media, and site-specific factors that limit implementability. For some portions of the RM11E Project Area, including most of the Navigation Channel, a single remedial approach is identified in the BODR. For other areas, including the areas behind, beneath and around the Glacier NW and Cargill main docks, several separate and distinct remedial approaches are identified for further evaluation under the Remedial Design Work Plan (RDWP) to address significant site-specific structural engineering, facility operation, and access issues particular to these active marine terminals, as discussed in Sections 8 and 9.

The objectives of the BODR, from Section 3.2 of the RD SOW, are listed below. The sections of the BODR where those objectives are addressed are in parentheses.


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Summarize existing site conditions, implementability, site factors, and refinement of the conceptual site model (CSM) pertaining to the RM11E Project Area (Section 2).

Summarize design criteria applicable to the RM11E Project Area as described in the Remedial Design/Remedial Action Handbook (EPA, 1995) (Section 3).

Identify implementable remedial technologies and then screen those technologies for the portions of the RM11E Project Area requiring remediation (Sections 4 and 5).

Evaluate promising remedial technologies for the RM11E Project Area based on effectiveness, implementability, consistency with the ROD, and cost (Section 5).

Identify a preferred remedial approach for the RM11E Project Area (Section 6).

Identify long-term monitoring and maintenance considerations for the RM11E Project Area (Section 7).

Identify design studies and other information that may be necessary for RD, if any, to address proposed remedial technology means and methods for the RM11E Project Area (Section 8).

Describe a sequencing plan and an overall schedule to complete the design studies, RD, and remedial action (RA) for the RM11E Project Area (Section 9).

Discuss modifications (if any) to the RM11E Project Area now that the ROD has been issued, and taking into consideration the complete current data set for the site (Section 2.1).

Together with the PHSS ROD, four previous RM11E studies serve as primary resources for completing the BODR:

Final RM11E Field Sampling and Data Report (GSI, 2014)

Final RM11E Porewater Characterization Report (SEE et al., 2015)

Draft RM11E Implementability Study Report (DOF et al., 2015) 1

Final RM11E Recontamination Assessment Report (GSI and DOF, 2018)

The Sampling and Data Report (GSI, 2014) provides the results of the 2013-2014 surface sediment, bank soil, upland (subsurface) soil, and groundwater sampling efforts at RM11E along with prior historical sampling results. The work included the collection and analysis of 22 surface sediment samples and 9 surface soil samples, completion and soil sampling of 5 upland soil borings used to install monitoring wells, and 2 rounds of groundwater quality monitoring from 7 upland wells. Appendix K of the report provides a 2014 compilation of known historical data from surface and subsurface sediment sampling, sediment trap sampling, and soil sampling at RM11E. 1 The July 2015 Implementability Study Report was submitted as a draft report to EPA. EPA provided comments in a May 2017 letter, indicating that no revisions of the report were required, but that comments should be considered during RD. EPA’s comments are incorporated in this BODR, and will be carried through to RD, as appropriate.


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Seven2 collocated surface sediment, surface water, and porewater samples were collected as part of a follow-up porewater characterization study in 2015. Those data and pertinent findings are provided in the Porewater Characterization Report (SEE et al., 2015).

The Implementability Study Report (DOF et al., 2015) identifies multiple site factors that impact the selection and implementation of a remedy at RM11E: facility operations, navigation clearance, construction access, a submarine cable crossing, remnant piles, debris, oversteepened slopes, structure stability, propeller wash, and wave action. The report discusses the implementability and constructability constraints of remedial technologies at the RM11E Project Area. These findings are further summarized in Section 2.5 of this BODR.

The Recontamination Assessment Report (GSI and DOF, 2018) addresses potential upland and in-water sources of recontamination after RAs are completed at the geographic locations within the RM11E Project Area where active remediation will likely occur. Findings from the report are summarized in Section 2.8 of this BODR.

1.2 Project Mile Baseline A project mile baseline (shown in blue in Figure 1-2) has been established to reference locations of site features within this report. The project mile baseline (blue line) runs roughly parallel to the shoreline and is positioned at or near the east edge of the U.S. Army Corps of Engineers’ (USACE) Willamette River Navigation Channel (Navigation Channel)3. Stationing along the project mile baseline is identified as project mile (PM), with each 0.1 mile shown in Figure 1-2. More detailed figures in this report show the PM stationing every 0.01 or 0.02 mile (~53 or ~106 feet [ft]), respectively.

The Navigation Channel line (shown in white in Figure 1-2), which was established by USACE, is located near the center of the river. Stationing along the Navigation Channel line is identified by RM designations based on the distance to the location from the mouth of the river and appears every 0.1 mile in Figure 1-2.4

1.3 Project Datum The horizontal datum is the reference system used to establish the mapping coordinates of the site and site features. The horizontal datum used in this report is Oregon State Plane North (North American Datum of 1983 [NAD83]).

The vertical datum is the reference system used to establish the elevations of the site and site features. Two vertical data references are used in this report:

North American Vertical Datum of 1988 (NAVD88)

Columbia River Datum (CRD)

2 Six samples from within the contaminated portions of the RM11E Project Area and one upstream reference sample. 3 A federal Navigation Channel, with an authorized depth of -43 ft CRD, extends from the confluence of the lower Willamette River with the Columbia River to RM 11.6. 4 The project baseline also differs by approximately 60 ft from the RM lines presented in the PHSS RI/FS reports and some previous RM11E project documents.


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NAVD88 is the primary vertical datum used in this report. The CRD is referenced with regards to vessel navigation and associated dredging. Figure 1-3 relates CRD and NAVD88 within the RM11E Project Area as of 2013.5

There are several regulatory criteria related to elevation to be considered for RD: Oregon Department of Environmental Quality (DEQ); project lines established in the ROD; and National Oceanic and Atmospheric Administration’s (NOAA) habitat equivalency analysis (HEA) boundaries. The various elevation-related criteria are presented in Table 1-1.

1.4 Report Organization The BODR is organized as follows:

Section 1 Introduction

Section 2 Site Conditions

Section 3 Design Criteria

Section 4 Remediation Technology Screening

Section 5 Remediation Technology Evaluation

Section 6 Site-Specific Remedial Approach

Section 7 Performance Standards and Monitoring

Section 8 Design Studies

Section 9 Remedial Design Sequencing

Section 10 References

Tables

Figures

Exhibits

Appendices

The organization of the report is slightly modified from the report organization stated in the BODR Work Plan (Section 4, Deliverables) in that the organization of topics in Section 2 has been revised, and Section 3 described in the Work Plan (Modifications to the Project Area) is now included as part of Section 2.1.

5 In the PHSS Draft FS, the difference between CRD and NAVD88 is shown as 5.0 ft. As shown in Figure 1-3, the average

value of this conversion for the RM11E Project Area is 5.3 ft, based on 2013 data provided by DEA.


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2. Site Conditions

2.1 RM11E Project Area The RM11E Project Area is defined in the SOW included in the April 2013 AOC and shown in the RM11E Base Map (Figure 2-1). The RM11E Project Area lies between approximately RM 10.9 and RM 11.6 along the east bank of the Willamette River within the upstream portion of PHSS. The RM11E Project Area covers approximately 36 acres, including more than 3 acres of riverbank. For this BODR, the “riverbank areas” are defined as the areas that are situated between an elevation of 13 ft NAVD88 and the top of bank6, which corresponds with the eastern edge of the RM11E Project Area (Figure 2-1). Figure 2-2 is a cross section schematic of the Willamette River that references the sampling area, elevation, and media terminologies used in this BODR.

Modifications to the RM11E Project Area are not proposed at this time. However, should new data become available that change the sediment management area (SMA) footprints (including the results of the Pre-Remedial Design Investigation and Baseline Sampling and future RD studies), modifications to the RM11E Project Area boundary will be considered accordingly.

2.2 RM11E Upland Area and Source Control Status The upland area is located inland from the riverbank, outside of the RM11E Project Area. For consistency with the Recontamination Assessment Report, the RM11E upland area is defined as the adjacent land area that currently has one or more potential pathways to the RM11E Project Area. The upland area encompasses the shoreline properties (Figure 2-1), the current stormwater drainage area (Figure 2-3), and any contaminated groundwater plume that may extend beyond the stormwater drainage area (see Section 2.8.1). Figure 2-3 includes approximately 150 acres of historical stormwater drainage areas to City outfalls OF43 and OF44A that were diverted to the eastside combined sewer overflow (CSO) abatement tunnel (Eastside CSO Tunnel) in 2011. A portion of these former RM11E drainage basins discharge to the river during infrequent CSO overflow events.

The upland area shown in Figure 2-3 includes waterfront and inland areas within the historical Albina district, where there have been commercial and industrial operations since the late 1800s. Historical uses included commercial and industrial facilities, a shipbuilding and repair facility, docks and wharfs, roadways and railways, and electrical facilities, including substations and equipment repair facilities. Legacy sediment contamination found in the RM11E Project Area is largely the result of these past activities.

6 The “top of bank” is defined for the RM11E project as the elevation where the bank slope begins to flatten out. Note that while the RM11E “riverbank” area in this BODR is defined as extending to the top of bank, EPA’s previous “riparian zone” investigations and “riverbank soil” references refer to elevations between mean high water (approximately 13 ft NAVD88) and ordinary high water (OHW) (+20 ft NAVD88); however, the schematic (Figure 2.2-1 from the Final RI Report) shows the top of bank as being just a couple ft higher than OHW, which is different than the setting at RM11E, where the bank begins to flatten out at an elevation of approximately 35 ft NAVD88.


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The RM11E Project Area and uplands continue to be used for commercial operations, maritime activities, and upland transportation (roadways and rail). Releases of contaminants of concern (COCs) to the river from these uses have been largely eliminated by banning the use of certain chemicals (e.g., polychlorinated biphenyls [PCBs]), improved environmental management, and significant source control work conducted by upland property and facility owners and operators and overseen by DEQ. Cleanup sites located within the current and historical stormwater drainage areas are shown in Figure 2-3.

Table 2-1 is a Source Control Sufficiency Assessment Summary Matrix (Sufficiency Matrix) that was developed by DEQ and EPA (EPA, 2018b; EPA and DEQ, 2018). The Sufficiency Matrix identifies the potential recontamination sources and pathways at RM11E and categorizes the status of each source. EPA and DEQ have determined that potential recontamination sources within the RM11E upland area have been adequately investigated and controlled with the following conditions and exceptions:

Sources are conditionally controlled7:

o Tarr, Inc. (Tarr), Groundwater Pathway

o Glacier NW’s River Street Terminal (Glacier NW) Stormwater Pathway

o Cargill-Irving Terminal (Cargill) Stormwater Pathway

o Ross Island Sand & Gravel (RIS&G) Riverbank Erosion Pathway

o Union Pacific Railroad (UPRR) Albina Yard

o 2100 N. Albina (Albina Development Project) Stormwater and Groundwater Pathways

o Oregon Department of Transportation (ODOT) Fremont Bridge (and WR-306) Stormwater Pathway

Sources are not sufficiently assessed or controlled:

o ODOT/Stan Herman/KF Jacobson Leased Property Riverbank Erosion Pathway

In addition to the upland cleanup Sites, DEQ and EPA also include the Upriver (i.e., incoming) sediment pathway and the In-Water SMA (Sediment, Porewater, and Overwater Pathways) in the Sufficiency Matrix. The Upriver sediment pathway is classified as conditionally controlled and will be addressed through site-wide baseline and long-term monitoring. The In-Water SMA is not controlled and is the focus of this RD work.

Although some upland and upriver source control efforts are ongoing, EPA and DEQ have made the determination that sources are sufficiently understood and controlled, and RD and RA can move forward in the RM11E Project Area (EPA, 2018c). Based on the work conducted by the RM11E Group during the Recontamination Assessment, the RM11E 7 Cleanup sites that have been classified as “conditionally controlled” are: (1) sites where sources have been identified and are not anticipated to require source control measures (SCMs) pending additional evaluation; or (2) sites with SCMs in place and performance monitoring is required to determine the sufficiency of those SCMs.


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Group generally agrees with EPA and DEQ’s conclusions, but notes the need for confirmation that the Upriver sediment pathway is controlled (see Section 2.8.2), and a lack of data at the Stan Herman property, as further discussed in Section 2.7.2 of this BODR.

Completion of ongoing source control and investigation activities lies within the jurisdiction and authority of DEQ and EPA. To the extent that additional information becomes available to the RM11E Group, it will be considered, as needed, during RD to determine whether cleanup can go forward and, if potential sources remain, how those sources should be addressed.

2.3 Shoreline Ownership and Operations As in much of PHSS, the river at and near RM11E was modified and specifically deepened to make it useable for navigation and commercial shipping operations. Certain shoreline areas have been filled and riverbanks armored in conjunction with development of waterfront properties. The RM11E waterfront area consists of 7 properties, 1 bridge crossing, 2 live cable crossings, and 10 active outfalls, as shown in Figure 2-1. The waterfront properties currently contain industrial or commercial operations, artists’ studios, and vacant land. Shoreline properties, a bridge crossing, cable crossings, and outfalls are briefly identified below, moving from north to south along the river (i.e., moving upstream). Additional detail on current and future waterfront operations is provided in Section 3 of the Implementability Study Report (DOF et al., 2015).

Shoreline Properties Sakrete. Central Premix Concrete Products Co. (a Sakrete affiliate) combines

Portland cement and aggregates that are bagged and resold at the Sakrete property. Aggregate and cement are received in bulk quantities via truck. Aggregate is unloaded on the ground into bunker areas, while the cement is pneumatically pumped into a closed silo vented to a bag house (Central Premix, 2012). Waterfront facilities include an approximately 185-foot-long inactive dock.

Stan Herman. This property previously contained a warehouse-type structure that was built on pilings over the riverbank. The structure was destroyed in a fire on May 14, 2017. Following the fire, EPA performed an emergency response between September 2017 and March 2018 and removed asbestos-containing building debris (warehouse building remains, residual warehouse contents, wharf decking, etc.) (Ecology and Environment, 2018). As part of the response effort, EPA added 6-inch minus rock to the upper portions of the riverbank. Lower portions of the riverbank are unarmored, and contain native riverbank soil and shoreline sediment with remnant piling and cross-bracing.

State of Oregon/ODOT. KF Jacobsen & Co., a sister company of RIS&G, leases ODOT property (under the Fremont Bridge) for a portion of the Albina Asphalt facility. The “hot mix” facility uses recycled asphalt, aggregate, hot asphalt, and sand to make asphalt paving. In addition to receiving aggregate from the barge dock it shares with RIS&G, the property receives recycled asphalt by truck. The recycled asphalt is crushed onsite and conveyed to storage piles placed under the Fremont Bridge (City, 2009).


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RIS&G. This property contains a portion of the KF Jacobsen & Co.’s Albina Asphalt facility and a previously operated concrete batch plant where raw aggregate is unloaded from barges using a clamshell bucket crane and stored in piles. The plant also accepts broken concrete pavement (construction debris), which is loaded onto barges at the dock and transported to the upriver Ross Island Lagoon for use as fill material. Barges are moored to mooring dolphins; a shuttle system is used to move barges approximately 500 ft along the river frontage (see Figure 5-1a).

Glacier NW. The River Street Terminal is a deep-water import terminal and the regional headquarters for Glacier NW’s Oregon and southwest Washington operations. As Glacier NW’s only cement terminal in the State of Oregon, the River Street Terminal receives bulk quantities of cement from oceangoing vessels that it distributes via rail and truck from the terminal to customers at 35 ready-mix concrete plants (including those of its competitors) and other customers in the Pacific Northwest. Glacier NW serves markets from the Oregon Coast, down to the California border, inland to central Oregon and Idaho, and north into British Columbia and Alberta, Canada. The company has approximately 50 employees at the River Street Terminal.

Waterfront facilities at the River Street Terminal include two docks. The upstream (main) dock is approximately 400 ft long and is used by ocean-going vessels. The downstream (barge) dock is infrequently used for mooring barges. Bulk cement delivered to the River Street Terminal is pneumatically conveyed from vessels at the main dock to upland storage buildings (11 silos and a dome), and then loaded into trucks and railcars for offsite delivery.

Unkeles. This property is used as artists’ studios and has no riverfront access or activity; its river frontage rights are owned by Cargill (Unkeles, 2014). For this BODR, the waterfront area adjacent to the Unkeles property is addressed as part of the Cargill property.

Cargill (currently operated by Temco, Inc.). The Irving Terminal provides interim bulk storage for transfer of grain, primarily wheat, to and from trucks, railcars, barges, and ships (Cargill, 2014). Listed from downstream to upstream (north to south), the facility includes a mooring dolphin with a bridge to the bank located in front of the Unkeles property; a remnant structure approximately 100 ft downstream of the main dock; a main dock for ocean-going vessels; and a barge dock approximately 350 ft upstream of the main dock. Note that the barge dock is outside of the RM11E Project Area. A soldier pile retaining structure (not visible) is located landward of the main dock near the top of bank, and a steel retaining wall is located along the shoreline between the main dock and the barge facility dock.

The Irving Terminal has 45 employees and contractors, and receives grain from farms in North Dakota, South Dakota, Montana, Idaho, Washington, and Oregon. The Irving Terminal is Cargill’s only terminal in the Northwest that can directly receive soft white wheat from local farmers.


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Bridge Crossing Fremont Bridge. The bridge is owned and maintained by ODOT and is part of

Interstate 405 (I-405). Most of the stormwater runoff from the Fremont Bridge drains directly from the bridge to the river through scuppers. The eastern and western approaches to the bridge drain to outfalls WR-306 and WR-307, respectively (Herrera, 2015).

Cable Crossings Level 3 Communications submarine cable crossing. In August 2000, a 15-foot-wide

easement was granted to Level 3 Communications to replace four fiber optic communication cables in a conduit under the Willamette River. The submarine fiber optic cable crossing is located under the southern edge of the Fremont Bridge.

PacifiCorp submarine cable crossing. This medium-voltage electric cable crossing is owned by PacifiCorp and consists of seven submarine cables that extend from a cable vault on the Unkeles property to the west side of the river. All seven cables are energized. The cables originate from the nearby Albina Substation where incoming 115 kilovolt (kV) transmission lines are stepped down to 11 kV to provide power to a portion of downtown Portland (DOF and GSI, 2013).

Century Link communications cable crossing. A communications cable may have been installed within the same right of way across the river as the PacifiCorp submarine cable crossing. Investigations are underway to determine if the cable was actually installed, and if so is it still in use. The status of the communications cable will be determined as part of the Alternatives Evaluation Report.

Outfalls Stormwater runoff from the RM11E Upland Area to the RM11E Project Area is conveyed mostly through the stormwater outfalls. Ten active stormwater outfalls drain into the RM11E Project Area, as listed below and shown in Figure 2-1.

Sakrete: WR-291

ODOT: WR-306, which drains portions of Interstate 5 (I-5) and interchange ramps connecting the Fremont Bridge (I-405) with I-5

Glacier NW: WR-350, WR-351, and WR-352

City: OF43, OF44, and OF45

Cargill: WR-341 and WR-344

2.4 Physical Site Setting 2.4.1 Regional Geologic and Seismic Setting On a regional scale, the site lies within the Willamette-Puget Sound lowland trough of the Cascadia convergent tectonic system (Blakely et al., 2000). The lowland areas consist of broad, north-south-trending basins between the Coast Range to the west and Cascade Range to the east. The site is located approximately 50 miles inland from the down-dip edge of the Cascadia Subduction Zone (CSZ), an active convergent plate boundary along which


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remnants of the Farallon Plate (the Gorda, Juan de Fuca, and Explorer Plates) are being subducted beneath the western edge of the North American continent. The CSZ is a broad, eastward-dipping zone of contact between the upper portion of the subducting slabs and the overriding North American Plate, as shown in Figure 2-4.

On a local scale, the site lies within the Portland Basin, a large, well-defined, northwest-trending structure characterized as a right-lateral, pull-apart basin in the forearc of the CSZ. The Portland Basin is bounded by high-angle, northwest-trending, right-lateral strike-slip faults considered to be seismogenic; however, the relationship between specific earthquakes and individual faults in the area is not well understood because few of these faults are expressed clearly at the ground surface. A limited number of intrabasin faults has been mapped on the basis of stratigraphic offsets and geophysical evidence, and the site is located in close proximity to the inferred traces of the Portland Hills Fault and East Bank Fault indicated on published local fault maps (Personius et al., 2003), and are shown in Figure 2-5.

The U.S. Geological Survey (USGS. 2014) has identified two primary types of seismic sources that are most likely to affect the RM11E Project Area: CSZ events related to sudden slip between the upper surface of the Juan de Fuca Plate and the lower surface of the North American Plate; and local crustal events associated with movement on shallow local faults within and adjacent to the Portland Basin.

2.4.2 Local Geologic Setting The geologic deposits beneath and adjacent to the RM11E Project Area, from the surface downward, consist of artificial fill, finer-grained (silty) alluvial deposits, coarser-grained (gravel) alluvium and flood deposits, and sands and gravels of the Troutdale Formation. A conceptual projection of these units on the river bottom is provided as Figure 2-6a8. Geologic cross sections oriented perpendicular to and parallel to the riverbank are included as Figures 2-6b and 2-6c, respectively. The geologic units are as follows:

Artificial Fill. The base of the artificial fill at each of the monitoring well locations ranged from approximately 20 to 24 ft below ground surface (bgs) (with a bottom elevation of approximately +10 ft NAVD88). The fill is primarily composed of silt with varying amounts of clay, sand, and gravel, and commonly included construction debris (e.g., concrete, bricks, and metal) and woody material. The presence of the silt matrix generally reduces the permeability of the unit. The fill unit in this area forms a wedge that is thickest at the riverbank and thins moving inland. The inland extent of the fill approximately coincides with N. River Street. Historical aerial photographs show that filling in much of the area began in the late 1940s and essentially was completed in the late 1960s. Fill placement is not well-documented and is generally not engineered, resulting in the variable composition and density as observed in historical and recent geotechnical data. The face of the bank is steep and generally armored along the upper portions.

8 Figure 2-6a (and other figures prepared by GSI) contours are based on survey data from 2009 – 2011. The 2018 bathymetry and topography are used in the cross sections in Sections 5 and 6 (and other figures prepared by DOF). The 2018 bathymetry and topography will also be used in all future RD work.


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Silty Alluvium (ML)9. The finer-grained flood and/or alluvial deposits encountered below the base of the fill typically consisted of silt with some clay and fine sand and occasional wood debris. Sand and gravel interbeds of varying thickness are present throughout the silty alluvium unit. The thickness of the silt unit generally ranges from 11 to 16 ft across much of the RM11E Project Area (with an average bottom elevation, where present, of approximately -3 ft NAVD88).

The silty unit was observed to be much thicker, 57 ft (bottom elevation of about -40 ft NAVD88), in the deep monitoring well boring (RM11E-MW003d), which was installed at the northern end of the Cargill property and the outlet of a former unnamed gulch. The underlying alluvial gravel in this area was not encountered. Consequently, the silty unit directly overlies the Troutdale Sand (as described below).

Gravel Alluvium (GM)10. This unit consists of the coarser-grained catastrophic flood deposits mainly consisting of poorly sorted gravels in a sandy silt matrix. The coarse-grained gravel alluvium is expected to provide relatively moderate groundwater flow into the river compared to the overlying fill and silty alluvium. Although the contact between the gravel alluvium and underlying Troutdale Formation is difficult to distinguish based on the existing information, this unit is estimated to be approximately 30 to 35 ft thick in the upland area, with a bottom elevation between -30 and -35 ft NAVD88. Based on pile driving records for some of the offshore structures, the bottom elevation of the gravel alluvium likely decreases toward the Willamette River. The gravel alluvium comprises much of the submerged riverbank slope, as shown in Figure 2-6a. The gravel alluvium unit was not observed in the deeper RM11E-MW003d boring and appears to have been eroded by a paleochannel that since has been filled by silty alluvium (Figure 2-6b).

Troutdale Sand (SP). This unit consists of clean well-sorted (poorly graded) sand that appears to have been deposited within a paleochannel carved into the coarser-grained Troutdale Gravels (see below) and does not appear to be laterally extensive (Figure 2-6c). The Troutdale Sand unit in this area begins approximately 70 to 75 ft bgs (top elevation of approximately -35 to -40 ft NAVD88) in the upland area and is approximately 23 to 27 ft thick (with an average bottom elevation of approximately -63 ft, which is below the base of the river). This paleochannel is interpreted to outcrop below the base of the Willamette River in this area, but the actual extent is unknown.

Troutdale Gravels (GM). This unit is described by Madin (1990) as moderately cemented to well-cemented conglomerates with minor interbeds of sandstone, siltstone, and claystone. Non-cemented or weakly cemented Troutdale Gravel has been identified in explorations completed in the RM11E Project Area. These non-cemented or weakly cemented gravels can be difficult to distinguish between alluvial gravels. The Troutdale Gravel underlies the gravel alluvium deposits

9 This unit is also referred to as “Fine-grained Pleistocene Flood Deposits and Recent Alluvium (Undifferentiated)” in Section 3.1.2.1.2 of the Final RI. 10 This unit is also referred to as “Coarse-grained Pleistocene Flood Deposits (Gravels)” in Section 3.1.2.1.3 of the Portland Harbor Final RI Report.


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throughout the area except for the Troutdale Sands filling the paleochannel. Although no local borings are available to confirm this, the Troutdale Formation (including both sands and gravels) beneath the RM11E Project Area is estimated to be 150 to 200 ft thick (Swanson et al., 1993).

Figure 2-6a includes an interpretation of the geologic units underlying the river bottom of the RM11E Project Area. These units are covered in most places by a layer of more recent Willamette River alluvium (sediment) (see Figure 2-6b). These alluvial deposits are a mixture of silts, sands, and gravels that are reflective of both incoming sediment loads from upstream, and reworking of material that is present along the riverbanks and river bottom. The thickness of these alluvial units is variable, uncertain, and difficult to distinguish from the underlying gravel alluvium. A physical description of this Willamette River alluvium (i.e., sediment characteristics) is provided in Section 2.4.3.

2.4.3 Physical Sediment Data The channel bathymetry and sediment grain size data collected from within the RM11E Project Area are shown in Figure 2-7a-b and Figure 2-8a-b for surface and subsurface sediment, respectively. Because grain size was analyzed and reported using slightly different methods over time, the available grain size data presented in Table 2-2 have been grouped into gravels, sands, silts, and clays with the relative percentage of each group depicted for surface and subsurface sediment in Figure 2-7a-b and Figure 2-8a-b, respectively.

To augment the empirical grain size results performed on only a subset of samples, the visual sediment and soil description logs were reviewed in order to assign lithologic descriptions to these RI samples. Table 2-3 contains these visual classifications, which were assigned as follows:

Predominant Grain Size. Because sample lithology and relative percentage of clay, sand, gravel, and silt can vary within a single sample interval, a simplified determination of the predominant grain size within each sample interval was assigned. Figure 2-9 shows these predominant grain size classifications for surface and subsurface data.

Primary Description ID. A number is assigned to the primary descriptions from finest (1) to coarsest (17) sediment/soil type along with a letter code for the Predominant Grain Size (C for clay, M for silt, S for sand, and G for gravel). A summary of the predominant and primary descriptions is provided in Exhibit 2-1. This primary description ID is also used as a shorthand sediment description in the remedial technology cross sections in Section 5.1.

Primary Description Type. Expanding on the predominant grain size assignment, a description of the predominant sediment or soil type (e.g., silty sand) was developed for each sample interval. This includes generalized geologic descriptions that have been normalized to limit the number of unique descriptions per data set.


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Exhibit 2-1. Summary of Visual Classification Scheme Predominant Grain Size

ID Visual Description

Clay C-1 Silty Clay Silt M-2 Clayey Silt Silt M-3 Clayey Sandy Silt

Silt M-4 Silt Silt M-5 Sandy Silt Silt M-6 Sandy Gravelly Silt

Silt M-7 Gravelly Silt

Sand S-8 Clayey Sand

Sand S-9 Clayey Silty Sand

Sand S-10 Silty Sand Sand S-11 Sand Sand S-12 Silty Gravelly Sand

Sand S-13 Gravelly Sand

Gravel G-14 Silty Gravel Gravel G-15 Silty Sandy Gravel

Gravel G-16 Sandy Gravel

Gravel G-17 Gravel

Secondary Description Type. A secondary lithology was assigned when more than approximately 25 percent of the sample interval contained a different material (see Table 2-3).

Organic Matter Content. Organic matter content was described as “High”, “Low”, or “Not Detected” based on a qualitative assessment of the sediment logs. Organic matter content was considered “Low” for records with a small number of wood fragments or organic odor only. For example, organic matter content for a sample with two wood fragments located in the same thin layer and no organic odor was considered “Low.” Organic matter content was considered “High” for samples with multiple wood fragments, leaf litter, or if there were a small number of wood fragments combined with organic odor (see Table 2-3).

Based on review of both the empirical grain size data (Table 2-2 and Figures 2-7 through 2-9) and the visual descriptions (Table 2-3 and Figure 2-9), sands are the predominant grain size in the RM11E Project Area and are often encountered with a mixture of silt and/or gravel. Based on available empirical grain size data, the average grain size distribution for RM11E surface and subsurface samples is: 57 percent sand, 21 percent gravel, 18 percent silt, and 4 percent clay. This is comparable to the visual observations of RM11E surface and subsurface sediment (Table 2-3), which breaks down as: 38 percent sand, 25 percent gravel, 33 percent silt, and 4 percent clay. As shown in Figure 2-7b and Figure 2-9, the fine-grained silts (depicted as green in the figures) and clays (depicted as blue in the figures) are present primarily in the nearshore areas behind and/or near docks and other structures. A relatively fine-grained alluvial lobe (i.e., ridge) of sediment is also observed near the eastern end of the PacifiCorp electric cable crossing (approximately RM 11.35), with higher percentages of silt observed in the subsurface (Figure 2-8b and Figure 2-9). Figure 2-7a and Figure 2-9b also


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indicate higher silt content in the Navigation Channel near RM 10.9; however, the empirical grain size data provide limited information because the area contains exposed gravels with fine-grained material accumulated in the ripples (which are evident in the bathymetry in this area). The presence of large gravel precluded numerous grab and core samples from being successful in this area and, therefore, the successful samples are biased toward the easier to sample fine-grained fractions. This is also true upstream of the Fremont Bridge where field experience shows that some of the riverbed has a hardpan consistency and thus successful samples also favored the sandy and finer-grained areas. In addition, large gravels that made their way into a grab or core sample would have been excluded from the sample container and thus the overall percentage of gravels is underestimated where gravel is present.

Table 2-2 includes the total organic carbon (TOC) data and total solids data associated with samples where empirical grain size data are available. The range and average percentages observed in this data set are summarized below:

Total solids. Ranges from 39.1 to 90.2 percent, with an average value of 69.8 percent.

TOC. Ranges from 0.02 to 3.06 percent, with an average value of 1.08 percent.11

Black carbon was also analyzed for in six sediment samples (Table 2-2) and was detected in two of the samples at values of 0.17 percent and 4.66 percent. Black carbon was not detected in the other four samples, which had method detection limits (MDLs) of 0.16 or 0.18 percent (Table 2-2).

In addition to the grain size, TOC data, and total solids data, 13 sediment samples were also selected for analysis of geotechnical parameters consisting of Atterberg limits, specific gravity, gravimetric water content, and bulk density to inform the RD. Those samples were selected to provide a general representation of sediment types. The geotechnical data are provided in Table 2-4 and summarized below:

Specific gravity. Ranges from 1.66 to 2.89, with an average value of 2.12.

Bulk density. Ranges from 1.21 to 1.80 grams per cubic centimeter (g/cm3) with an average value of 1.58 g/cm3.

Gravimetric water content. Ranges from 14 to 103 percent, with an average value of 46.3 percent.

Atterberg limits. Eight of the 13 samples analyzed for Atterberg limits had non-plastic results. Of the remainder, the average liquid limit, plastic limit, and plasticity index was 42.1 percent, 33.4 percent, and 8.76 percent, respectively.

2.4.4 Local Hydrogeologic Setting The depth to groundwater in the RM11E upland area ranges from approximately 17 to 26 ft bgs (elevation 9 to 18 ft NAVD88). The general groundwater flow direction is west-southwest toward the Willamette River throughout most of the year. Except for the massive

11 Because successful sediment samples are biased toward the easier to sample fine-grained fractions, the TOC concentrations are also likely biased high relative to the overall riverbed lithology.


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silt layer contained within a former paleochannel (see Section 2.4.2), shallow groundwater levels respond quickly to seasonal and diurnal tidal effects observed in the river, but are muted in amplitude compared to the variations observed in the river stage. Daily tidal fluctuations in river stage typically range from 3 to 5 ft during the late summer and fall months when stage/discharge is lowest, and from 1 to 2 ft during the late winter and spring months when stage/discharge is highest. Seasonally, when the river is high, there are instances when surface water levels rise above groundwater elevations resulting in short-term gradient reversals and limited recharge of surface water to groundwater.

Groundwater gradients and seepage rates are described in Section 5.2.1 and Appendix B.4 of the Recontamination Assessment Report. Groundwater gradients within the shallow system are generally steep immediately adjacent to the river and flatten out away from the riverbank (EPA, 2016a). An average groundwater gradient to the river of 0.0015 foot/foot was used for the calculation of seepage velocities based on the gradients between shallow upland wells, which are less influenced by changes in the river level.

Using the available data for the RM11E site, the seepage velocities (vs) range from approximately 10 to 150 cm/year using the following equation and input parameters:

Equation 1

𝑣𝐾𝑖𝑛

where:

Hydraulic conductivity (K) range: 1 x 10-4 to 1 x 10-3 cm/s

Average groundwater gradient to the river (i): 0.0015 foot/foot

Effective porosity (ηe): 0.4

2.4.5 Climate Change and Flood Rise Considerations The Willamette River watershed is historically rain-dominant, which means that peak flows (i.e., discharge) have occurred each year during the winter months as a result of rainfall and snow, with only modest peak flows occurring during the spring because of snowmelt (RMJOC, 2018). Evaluations of the impact of climate change on river flows in the Willamette River watershed suggest an increase in peak flows in the winter from more frequent fall and winter rain events, and a decrease in flows during the summer as a result of lower snowpack amounts (RMJOC, 2018). Based on research conducted to date, the most proximal climate change predictions to the RM11E Project Area were made in 2018 by the Bonneville Power Administration, USACE, and the U.S. Bureau of Reclamation, collectively known as the River Management Joint Operation Committee (RMJOC). The RMJOC study used a set of naturalized streamflow data sets derived from CMIP-5 Global Climate Model projections to project climate change impacts in the Willamette River watershed (RMJOC, 2018). Projections for the Willamette River, at Willamette Falls, are provided in Figure 2-10 and show the following:


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Fall and winter flows are likely to increase through the 21st century. On average, the 90th percentile winter flow rates are projected to increase by approximately 25 percent.

The frequency and intensity of extreme high flow events will increase.

A slight decrease in spring flows is possible, with a longer period of low summer flows more likely.

The ROD indicates that flood rise uncertainties should be incorporated into the flood rise evaluation and cap design elements during RD. Further consideration of appropriate climate change and flood rise design elements is on hold pending receipt of EPA guidance for PHSS. Consideration of the upcoming guidance will be made in future RD phases for RM11E as the guidance becomes available.

2.5 Implementability Site Factors The Implementability Study Report identified and assessed the site constraints to be considered and addressed as part of RD for the RM11E Project Area (DOF et al., 2015). The engineering assessments identify 10 physical conditions and site activities, referred to as “site factors,” that have a high potential to impact RD and implementation:

Facility Operations

Navigation Clearance

Construction Access

Submarine Cable Crossing

Groups of Vertical Pile Remnants

Large Undifferentiated Debris

Oversteepened Slopes

Structure Stability and Capacity

Vessel Propeller Wash

Wave Action

The site factors are summarized below. The Implementability Study Report includes additional detail. While the site factors are discussed individually for clarity, many areas in the RM11E Project Area that may require remediation have multiple site factors to consider. For example, some nearshore subareas will likely be subject to wave action, structural stability issues, oversteepened slopes, groups of vertical piling remnants, and large undifferentiated debris site factors, as well as construction access issues and facility operations issues. Remedial technologies will need to be tailored to accommodate the demands of each subarea.


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2.5.1 Facility Operations There are three major marine terminals in the RM11E Project Area (Cargill, Glacier NW, and RIS&G) as shown in Figure 2-11. The Oregon Department of Fish and Wildlife’s (ODFW) in-water construction season coincides (and conflicts) with the busiest periods of shipping operations at those facilities. Restricting remediation to the current July-October time frame provided in the Oregon Guidelines for Timing of In-Water Work (work window) will cause significant implementability challenges, as shown in Exhibit 2-2 and discussed in detail in Section 5.2.

Exhibit 2-2. Summary of Potential Timing Impacts on Remedial Alternatives

The Implementability Study Report recommends expansion of the in-water work windows to continue or complete RAs outside the period of peak shipping activities and sequentially remediate portions of the RM11E Project Area using a phased or staged approach, so that remedial work can be coordinated with facility-specific operations. In-water work windows are addressed in Section 6.2.5

2.5.2 Navigation Clearance Engineered capping in deep-draft navigation areas (i.e., the Navigation Channel, deep-draft berths at Glacier NW and Cargill, and associated approach areas) shown in Figure 2-12 is unlikely to be a viable option because of navigation clearance requirements. As indicated in the ROD Figure 28, before construction of a cap in a navigation area could occur, it would be necessary to pre-dredge the area to lower the bed to below the authorized navigation depth by the thickness of the cap plus an allowance/buffer zone for future maintenance dredging. In most cases this pre-dredging would generally result in full removal of impacted material before the desired depth for cap construction was reached, thus negating the need for a cap.

The Implementability Study Report recommends dredging as a remedial option in navigation areas where engineered capping, including low-profile and amended caps, is not viable. The RA dredge prisms will be considered as part of the Alternatives Evaluation and 30% Design, configured so that the RA will not result in immediate and/or later impediment to FMD portions of the SMA or to navigation dredging in areas adjacent to SMAs.


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2.5.3 Construction Access Numerous areas within the shoreline and berth area of the RM11E Project Area are not accessible from the water by conventional marine construction equipment or from upland properties because of waterfront structures, groups of vertical pile remnants, shallow draft areas, and steep shorelines, as shown in Figure 2-12.

The Implementability Study Report recommends use of remote access equipment, such as telescoping conveyor belts or slurry pipelines, to deliver capping materials in these difficult to access areas. For dredging in areas that cannot be accessed otherwise, the Implementability Study Report recommends use of shallow-draft marine construction equipment (e.g., small excavator dredges on portable barges), diver-guided hydraulic dredges, and implementing RAs that require only limited use of marine construction equipment (e.g., monitored natural recovery [MNR], enhanced natural recovery [ENR], and in situ treatment) where appropriate.

2.5.4 Submarine Cable Crossings As described in Section 2.3, two submarine cable crossings traverse the RM11E Project Area (Figure 2-11). Their presence precludes dredging as well as anchoring and spudding of marine construction equipment in the cable corridors.

The Implementability Study Report recommends conducting additional investigations to refine the location and burial depth of the energized cables, establish a no-dig zone in the area of the submarine cables, incorporate RAs involving only limited disturbance of sediment (e.g., MNR, ENR, and in situ treatment) where appropriate, and sand capping in areas outside of deep-draft navigation. At EPA’s direction12, PacifiCorp is evaluating the feasibility of relocating the electrical cable crossing outside of the area with contaminated sediment.

2.5.5 Groups of Vertical Pile Remnants Large areas of remnant timber piles exist in the Intermediate and Shallow Regions of the shoreline predominantly behind the Cargill main dock, and to a lesser extent north of the Glacier NW main dock (Figure 2-13a). Figure 2-13b and Figure 2-13c show views of the vertical pile remnants in and around the Cargill main dock. The closely spaced remnant piles are likely stabilizing the existing banks. Removal of remnant piles may diminish slope stability and could result in slope failures. Groups of vertical pile remnants limit access for marine construction equipment, prevent dredge buckets from achieving complete removal of target sediment, and complicate the placement of a cap by limiting the achievement of a uniform cap thickness. If left in place, piles that extend through the cap could diminish the cap effectiveness.

For capping within groups of vertical pile remnants, the Implementability Study Report recommends considering whether to cut off piles near the riverbed and increasing cap thickness to account for irregular placement around pile remnants. For dredging within groups of vertical pile remnants, the Implementability Study Report recommends considering the use of diver-operated hydraulic equipment to remove thin deposits of 12 EPA Review Comments, Draft Implementability Study Report, Supplemental Remedial Investigation/Feasibility Study, River Mile 11 East, dated July 31, 2015. Review comments dated May 12, 2017.


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sediment in limited areas. The Implementability Study Report also recommends the incorporation of MNR, ENR, and in situ treatment where appropriate.

2.5.6 Large Undifferentiated Debris Large undifferentiated debris is expected along the shoreline of the RM11E Project area, primarily within the extents of historical shoreline structures, as shown with green shading in Figure 2-13a. The debris will complicate and diminish the effectiveness of dredging, and its removal could potentially destabilize slopes.

The Implementability Study Report recommends limiting dredging in areas where large undifferentiated debris is expected in favor of applicable non-removal technologies (e.g., MNR, ENR, in situ treatment, engineered capping, and active capping). Where dredging is required, the Implementability Study Report recommends using: (1) mechanical dredging equipment and conducting pre-dredge practice sessions to learn how best to manage and reduce turbidity generated during removal of large undifferentiated debris, (2) contingency plans to map debris fields as they are uncovered, and (3) marine construction tools specific to debris recovery.

2.5.7 Oversteepened Slopes Much of the shoreline of the RM11E Project Area is oversteepened as shown in Figure 2-14 and potentially susceptible to slope failure or movement. Dredging or capping could adversely affect slope stability.

The Implementability Study Report recommends incorporating remedial technologies that will limit slope disturbance (e.g., MNR, ENR, and in situ treatment) where applicable. If it is necessary to cap or dredge in areas where active remediation is required, consider slope stabilization methods, such as rock buttressing and retaining walls at the toe of the shoreline slope, intermediate retaining walls along the shoreline slope, and the use of articulated concrete caps in areas of oversteepened slopes, possibly held in place by piles that are driven into deeper stable deposits.

2.5.8 Structure Stability and Capacity Numerous docks and structures in various structural conditions are present throughout the RM11E Project Area as shown in Figure 2-11. Most are located along the shoreline in areas of oversteepened slopes. Changes to soil loading conditions caused by dredging or capping activities can reduce stability and the capacity of these structures. Dredging to remove more than 5 ft of sediment at or near existing structures poses a higher risk to structure stability than does shallower dredging and cap placement. Cap placement around structures, depending on the condition of the structure and cap configuration, also poses a risk to structure stability.

The Implementability Study Report recommends using non-removal remedial technologies (e.g., MNR, ENR, in situ treatment, engineered caps, and active caps) where possible to limit dredging around structures. If necessary and practical, consider stabilizing slopes and structures to protect the integrity of structures during and following remediation.


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2.5.9 Vessel Propeller Wash Disturbance of sediment and capping material is possible from vessel propeller wash in vessel navigation and berth areas shown in Figure 2-15.

The Implementability Study Report recommends using armored engineered caps and active caps in areas of potential propeller wash to protect against erosion. Dredging should be considered in areas of deep-draft vessel navigation, where navigation clearances render armored capping impractical.

2.5.10 Wave Action Sediment and caps placed in the wave zone (elevation zero to +23 ft NAVD88) of the RM11E Project Area (Figure 2-15) are subject to erosion from vessel wakes and wind-generated waves.

The Implementability Study Report recommends considering dredging in the wave zone or, where deemed appropriate, using armored engineered caps and active caps to protect against erosion, and stabilizing oversteepened slopes where required for capping.

2.6 Remediation Thresholds (RTs) The nearshore and Navigation Channel sediment remedial action levels (RALs), and applicable principal threat waste (PTW) thresholds, established in the ROD are identified in Table 2-5. RALs are defined by EPA as “contaminant-specific sediment concentrations of focused COCs (contaminants of concern) used to identify areas where capping and/or dredging will be conducted to reduce risks more effectively than ENR (enhanced natural recovery) or monitored natural recovery (MNR).” The ROD also states that all areas with PTW will be addressed by active remediation, not MNR. Therefore, the lower PTW or RAL value was selected as the applicable threshold for active remediation for the nearshore and Navigation Channel areas. These concentrations, listed in Table 2-5, are collectively referred to as RTs throughout this BODR. Applying this approach, the ROD designated approximately 9.8 acres for active sediment remediation at RM11E primarily based on RT exceedances of PCBs and, to a lesser degree, RT exceedances of total DDx13, total polycyclic aromatic hydrocarbons (PAHs), and several dioxin/furan congeners. The areas designated in the ROD for active remediation are termed SMAs (see Section 2.7.1).

When the active remediation is complete, the ROD calls for the remaining sediment above cleanup levels (CULs), but less than the applicable RTs, to be remediated via MNR. The ability of MNR to achieve CULs will be confirmed through long-term monitoring across PHSS from RM 1.9 to RM 11.8 (i.e., site-wide). The ROD states that compliance with the CULs is expected to be measured over appropriate spatial and temporal scales, which are yet to be determined.

13 DDx is the sum of dichlorodiphenyltrichloroethane (DDT) and breakdown compounds dichlorodiphenyldichloroethane (DDD) and dichlorodiphenyldichloroethylene (DDE).


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2.7 Nature and Extent of Focused COCs RM11E sediment and soil sample locations are presented in Figures 2-16a-e. Sample locations with one or more RT exceedance are shaded orange in Figures 2-16a-e.14 Sample areas and media are shown in Figure 2-2. Sample location terminology is dependent on the elevation at which the sample was collected, and the penetration depth of that sample, defined in Exhibit 2-3 for the purposes of this BODR.

Exhibit 2-3. Sampling Areas, Elevations, and Media Terminology Sample Area Terminology

Sample Elevation Sample Start Depth

Sample End Depth

Surface Sediment Variable, but at or below 13 ft NAVD88

0 cm bml ≤ 30 cm bml1

Subsurface Sediment Variable, but at or below 13 ft NAVD88

Typically > 30 cm bml2

> 30 cm bml

Shoreline Sediment Approximately 13 ft NAVD88 See “surface” and “subsurface” sediment depths. Riverbank Soil Above 13 ft NAVD88 and below the

top of bank Top of Bank Soil Collected just upland of where the

riverbank slope begins to flatten out. At an approximate elevation of 35 ft NAVD88.

Upland Soil Inland from the top of bank Notes. 1 The vast majority of PHSS RI surface sediment samples targeted the upper foot (30.5 cm) of sediment, for consistency with the defined biologically active zone. However, there are samples throughout PHSS with end depths between 30.5 and 40 cm that have been included in the RI/FS database as surface sediment. Those samples fall outside of the RM11E Project Area and future sampling efforts will continue to target the upper 30 cm of material as “surface sediment.” 2 Typically, subsurface samples have a start depth greater than or equal to 30 cm; however, some samples (e.g., dredge characterization cores) that have been included in the RI/FS database as subsurface sediment, have a start depth of zero cm and an end depth greater than 30 cm. bml = below mudline cm = centimeter ft = feet NAVD88 = North American Vertical Datum of 1988 PHSS = Portland Harbor Superfund Site RI/FS = remedial investigation/feasibility study

2.7.1 Surface Sediment and Sediment Management Areas The lateral extent of the areas requiring active remediation (i.e., the SMAs) within PHSS will be delineated by surface and subsurface contamination above RTs and where exposure is occurring or has the potential for exposure. . Figures 2-17 through 2-22 present soil and sediment sampling results for the focused COCs: total PCBs; total PAHs; total DDx; 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PeCDD); 2,3,4,7,8-pentachlorodibenzofuran (PeCDF); and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), respectively, with each sample location shaded to indicate concentrations with respect to the RTs:

Red: > Nav Channel RT

14 Newly released data from the Pre-Remedial Design (Pre-RD) Footprint Report dated January 11, 2019, which was prepared by the Pre-RD Group and submitted to EPA pursuant to an Administrative Settlement Agreement and Order on Consent (ASAOC), Docket No. 10-2018-0236, is not included in the BODR tables or figures. After EPA has approved the data, the RM11E Group will include relevant data in future RM11E design studies and reports.


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Orange: between the Nearshore RT and the Nav Channel RT

Green: between the CUL and the Nearshore RT

Blue: below the CUL

A map outlining the footprint of the SMAs based on RT exceedances is shown in Figure 2-23. Focused COC concentrations in surface sediment collected from within the RM11E Project Area are shown relative to the associated RTs in Table 2-6 with detected concentrations that exceed RTs highlighted and detected concentrations that exceed CULs bolded for reference.

The SMAs shown in Figure 2-23 are clipped shoreward at an elevation of +13 ft NAVD88 and were generated using surface sediment sample results, including the shoreline surface sediment results. The SMAs used in this BODR are consistent with those that were conditionally approved by EPA for use in the Recontamination Assessment Report (GSI and DOF, 2018; EPA, 2018d) and include collocated (side-by-side) sample results, where available. Sample results from areas that were dredged following the collection of samples continue to be excluded because of the inapplicability to present conditions. Comparison of SMA maps for the individual focused COCs illustrates the greater data density for total PCBs as compared to the other focused COCs. Additional data will be collected during RD to refine SMA boundaries.

Although the shoreline surface sediment samples are also surface sediment, they are distinguished from bedded sediment in Table 2-615 and the BODR figures because they were collected manually at low water from areas along the shoreline (approximate elevation of 13 ft NAVD88) where potentially erodible accumulated sediment was observed. Fourteen of the shoreline sediment samples had concentrations that exceeded one or more RTs and thus the lateral extent of contamination up into the Riverbank Region in these areas will require further delineation during RD.

2.7.2 Riverbank and Top-of-Bank Surface Soil As part of the RM11E Supplemental RI/FS, two riverbank composite surface soil samples (samples SL035 and SL036) and seven top-of-bank composite surface soil samples (samples SL028 through SL034) were collected in locations where potentially erodible soils were observed to have a possible pathway to the river (GSI, 2014). While these riverbank and top-of-bank soil samples were not included in the delineation of SMAs (because they were collected at an elevation of more than 13 ft NAVD88), the focused COC results are shown relative to RTs in Table 2-6 and Figures 2-17 through 2-22. Comparison of these soil sample results to RTs is provided for reference purposes only because RTs do not apply to top-of-bank or monitoring well soil samples or non-erosive riverbank. Of these nine samples, one (SL033 by Cargill) had an RT exceedance for total PCBs with a concentration of 170 microgram per kilogram (ug/kg). Total PAH and total DDx concentrations were below RTs, and dioxin and furan analysis was not conducted on these samples.

15Alternate forms of compiling the data, such as by project area, will be considered during remedial design.


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In addition to data collected as part of the RM11E RI/FS and other data already included in the PHSS/RM11E databases, the following samples were collected by third parties:

Glacier NW collected two four-point composite samples of exposed, potentially erodible soils from the upper (GUB) and lower (GLB) riverbank in the southwest (upriver) corner of its property in October 2012. All soil sampling locations were collected above the OHW level and selected on the basis of their availability and accessibility. These data are presented in Glacier NW’s Riverbank Soil Source Control Screening Evaluation (ERM, 2013). These samples were analyzed for PCBs and PAHs. Of these results, one total PCB RT exceedance was observed in the GLB sample (260 ug/kg in sample LB-101012).

EPA collected 22 three-point composite samples of surface soil (within the upper 30 cm) from the riverbank area at the Stan Herman property following the emergency response actions that were taken for the warehouse fire (Ecology and Environment, 2018). As shown in Figure 2-17, 14 of the samples were collected above an elevation of 13 ft NAVD88 and are referred to as riverbank soil samples. The other 8 samples were collected along the waterline at an approximate elevation of 13 ft NAVD88 and are thus referred to as shoreline surface sediment samples. All 22 of the samples were analyzed for total PCBs, total PAHs and total DDx; five of the riverbank soil samples were also analyzed for dioxins and furans. None of the samples analyzed for total PCBs, total PAHs, or total DDx exceeded respective nearshore RTs. However, all riverbank soil samples analyzed for dioxin/furans exceeded the nearshore RT for PeCDD, and three of the five samples also exceeded the nearshore RT for TCDD. Based on nearshore RT exceedances in these riverbank soil samples, additional data for dioxins and furans in shoreline surface sediment samples and adjacent surface soil samples are necessary to determine if this area may pose recontamination risk to the RM11E Project Area in-water remedy. The March 2018 shoreline surface sediment samples collected by EPA are not included in the SMA delineations prepared in November 2017 and discussed in Section 2.7.116.

While these private riverbank and top-of-bank soil samples and the Stan Herman property shoreline sediment samples are not included in the PHSS/RM11E databases, the data have been tabulated for inclusion in Table 2-6 and Figures 2-17 through 2-22, where the focused COC results are shown relative to RTs and CULs.

2.7.3 Subsurface Sediment Focused COC concentrations in subsurface sediment collected from within the RM11E Project Area are shown in Table 2-7 and Figures 2-17 through 2-22. Detected concentrations that exceed RTs are highlighted and detected concentrations that exceed CULs are bolded for reference in Table 2-7. Improved mapping of subsurface RT exceedances will be accomplished using data collected as planned for the subsurface sampling program for 30% Design.

16 The former Stan Herman property shoreline surface sediment results (Table 2-6) were not available when the SMA memorandum was prepared (GSI, 2017). Because of the late timing of that data and because no RTs are exceeded in those shoreline sediment samples, the SMA footprints in this BODR remain unchanged. Additional data collection is anticipated during RD and the SMA footprints will be updated accordingly after that new data become available.


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Besides subsurface sediment samples collected as part of the RI, Table 2-7 also includes sediment characterization samples obtained before maintenance dredging events that are considered to represent post-dredge surfaces (a.k.a. leave surface). Table 2-7 does not include results for samples that were subsequently dredged. The locations of retained and excluded dredge characterization samples are shown in Figures 2-16a-e. While the “leave surface” characterization samples are included in this subsurface sediment evaluation out of conservatism; it is recognized that dredging activities may have affected contaminant concentrations (because of actual dredging depths achieved or residuals deposition) and applicability to current conditions is uncertain; therefore, these data may not represent the current subsurface conditions in these sample areas. As new sediment samples are collected by the RM11E Group during RD Sediment Characterization (see Section 8.1) in the areas where these leave surface samples had been collected, the new data will replace the leave surface sample data.

2.7.4 Total PCB Depth of Impact Evaluation As shown in Table 2-6 and Table 2-7, all samples were analyzed for PCBs, but only about half of the surface samples and a third of the subsurface samples were analyzed for the full list of focused COCs. Only one surface sediment sample exceeded the total PAH RTs; therefore, PAHs are not considered a driver for active remediation at RM11E. Similarly, only two RT exceedances of total DDx in surface sediment were observed, and those samples are collocated with elevated PCB results and biased high because of the conventional method of pesticide analysis (GSI, 2017). Therefore, total DDx is also not a driver of active remediation at RM11E. Consistent with the findings presented in the ROD, total PCBs and dioxins and furans are the risk-driving COCs at RM11E, with PCBs being the primary risk driver.

Given the greater density of available PCB data, shown in Figure 2-17, as compared to other focused COCs (Figures 2-20 through 2-22), the combined surface and subsurface PCB data set17 was evaluated to estimate the PCB maximum depth of impact (DOI) where RT exceedance was noted on the basis of available data. Table 2-8 shows that estimated PCB DOI (ft bml). Where a deeper sample was collected that had lower concentrations than the associated PCB RT, the DOI was determined to be delineated. For surface and subsurface samples without a “clean” sample below it, the DOI is shown with a greater than symbol (>), indicating that the vertical extent of contamination has not been determined.

To visualize the PCB DOI relative to site features, a Theissen polygon18 map was created and is shown in Figure 2-24. In Figure 2-24, the comparison of the colored polygons to the SMA boundary illustrates that much of the subsurface contamination generally falls within the same areas as those with surficial contamination (i.e., the SMA footprints). However, there are some areas outside of the SMA boundary where subsurface contamination above RTs may be present (e.g., see the orange polygon labeled “5”, located at approximately RM 11.25 in Figure 2-24). The areas where the PCB DOI has not been fully delineated are hatched for reference.

17 Most sediment cores were collocated alongside a surface sediment power-grab sample so that the data could be combined to evaluate the DOI. As such, the individual and collocated (where available) data were evaluated to determine the maximum DOI where a PCB RT exceedance was observed. 18 Thiessen polygons are used to define the area that is closest to each point relative to all other points. They are generated in ArcGIS and mathematically defined by the perpendicular bisectors of the lines between all points.


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Limitations of the DOI Evaluation This DOI evaluation was conducted using available data to better understand the nature and extent of material that exceeds RTs and, that, if within an SMA, will require active remediation. It is recognized that most of the RI data were collected more than 9 years ago. There are also uncertainties in the vertical and horizontal accuracy of the sample locations. Therefore, RD studies are needed to better refine the lateral and vertical extent of contamination (see Section 8.1).

2.7.5 Upland Subsurface Soil Table 2-7 includes two soil samples that were collected from each of the five monitoring wells installed as part of the Supplemental RI/FS (GSI, 2014). The sample depths (ft) are incorporated into the end of the sample ID (e.g., MWS001-5_24, represents a soil sample collected over the 5- to 24-ft-bgs sample interval). The upper sample represents a composite sample of the artificial fill and the lower sample is a composite collected from the upper 5 ft of the underlying silty alluvium. These soils are not considered to be erodible, but were collected for informational purposes and the results are considered in this BODR to evaluate the quality of the artificial fill underlying the riverbank armoring and vegetation.

Of the available total PCB, total PAH, and total DDx results, the total PCB results in soil collected from across the artificial fill unit in the soil boring for monitoring wells MW001 and MW005 on the Glacier NW property had RT exceedances19 (Table 2-7). No dioxin/furan data are available in the upland fill. The lateral extent of contamination in the fill is unknown. The riverbank is armored, and exposed shoreline and top-of-bank sediment and soil samples were collected, as described in Sections 2.7.1 and 2.7.2.

2.7.6 Groundwater The RM11E groundwater sampling locations are shown in Figure 2-25. Table 2-9 provides focused COC concentrations in groundwater collected as part of the Supplemental RI/FS (GSI, 2014). Detected concentrations are bolded and those that exceed CULs (where available) are highlighted for reference. No CULs have been established in groundwater for four of the five focused COCs. Of those focused COCs with established CULs (i.e., total PCBs and total DDx), there were no CUL exceedances for total DDx. The two sampling results with total PCB results that exceed the CUL are considered biased high because: (1) the detected PCB results are below CULs when summed using the RI summation rules (i.e., non-detects equal zero); and (2) the samples were not filtered and suspended solids in the water column, especially in MW001 where turbidity was observed, likely resulted in biasing the detections higher. As a result, the concentrations of focused COCs in groundwater are not indicative of a contaminant plume migrating in groundwater. This statement is consistent with the findings of the Recontamination Assessment Report (see Section 2.8.1).

2.7.7 Porewater The collocated RM11E porewater and surface water sampling locations are shown in Figure 2-25. Table 2-10 provides total PCB concentrations in porewater collected from the RM11E Project Area as part of the Porewater Characterization Report (SEE et al., 2015). Based on the

19 Comparison of these soil sample results to RTs is provided for reference purposes only because RTs do not apply to top-of-bank or monitoring well soil samples or non-erosive riverbank.


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evaluation of the sediment-exposed polyethylene and associated equilibration rates, two of the six porewater samples collected from the RM11E Project Area had results that were estimated by Massachusetts Institute of Technology (MIT) and deemed usable for the project (SEE et al., 2015). Both estimated PCB concentrations were reported at concentrations that exceed the groundwater CUL of 14 nanograms per liter (ng/L). Because EPA did not establish background concentrations in porewater, this CUL may be lower than current background concentrations. Additional information on the recontamination potential from porewater is presented in Section 2.8.2.

2.7.8 Surface Water The collocated RM11E porewater and surface water sampling locations are shown in Figure 2-25. Table 2-11a provides total PCB concentrations in surface water collected from the RM11E Project Area. Total PCB concentrations in surface water were estimated at six locations in the RM11E Project Area as part of the Porewater Characterization Report (SEE et al., 2015). The passive samples were collected from surface water-exposed polyethylene situated from zero to approximately 15 cm above the mudline. The estimated surface water total PCB concentrations were all detected at concentrations greater than the surface water CUL of 0.0064 ng/L.

In addition to the passive surface water samples collected as part of the RM11E Supplemental RI/FS, surface water samples were also collected from the RM11E Project Area (at sample location W023E; see Figure 2-25) as part of the PHSS Round 3 surface water sampling efforts in September 2006, November 2006, and March 2007 (Integral, 2006). Samples were collected from a vertically integrated water column using either a peristatic pump or an INFILTREX 300 pump system, which is used for the collection of samples of trace levels of organic impurities from large volumes of water. Table 2-11b shows focused COC concentrations in surface water from station W023E relative to CULs, where available. As with the passive sampling surface water results, PCBs were detected at concentrations greater than the surface water CUL in all samples.

Because EPA did not establish background concentrations in surface water, this CUL may be lower than current background concentrations and thus may not be achievable.

2.8 Recontamination Assessment Summary The Final Recontamination Assessment Report was provided to EPA and memorandum of understanding (MOU) Participants20 on November 9, 2018, and was approved by EPA on November 21, 2018.

The overall objective of the Recontamination Assessment Report was to evaluate the potential for recontamination of the actively remediated areas of RM11E following completion of the RA in the RM11E Project Area and to identify options for mitigating any recontamination potential that may exist. Specific objectives of the Recontamination Assessment Report were to:

20 EPA is the lead agency for the PHSS in-water cleanup and DEQ is the lead agency for upland cleanup pursuant to a 2001 MOU among EPA, DEQ, state and federal natural resource agencies, and six tribal nations (MOU Participants).


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Evaluate upland pathways (stormwater, groundwater, and riverbank erosion) and in-water pathways (inflows from upriver, resuspension of bedded sediments, porewater, and overwater structures and activities) to identify potential sources of recontamination and factors that may impact remedy effectiveness.

Evaluate whether current potential sources and pathways are adequately investigated and controlled.

Identify the evaluation’s limitations and identify remaining data gaps.

To achieve these objectives, the recontamination potential in the RM11E Project Area was evaluated in a semi-quantitative manner. The first step was to identify a subset of the PHSS COCs that have the potential to recontaminate remediated sediment in the RM11E Project Area (i.e., RM11E recontamination potential chemicals [RPCs]). Those RPCs are total PCBs, four dioxin/furan congeners21, arsenic, bis(2-ethylhexyl) phthalate (BEHP), and total petroleum hydrocarbons (TPH) Diesel (a.k.a. diesel-range hydrocarbons). The next step was to prepare a recontamination CSM (Figure 2-26, and Section 4 of the Recontamination Assessment Report) to identify potential recontamination pathways and describe site conditions. Based on the CSM, the RPCs then were carried forward into evaluations of the potential recontamination pathways.

To reiterate the findings as they relate to the objectives, this section of the BODR is organized as follows:

Upland Pathway Conclusions (Section 2.8.1)

In-water Pathway Conclusions (Section 2.8.2)

Recontamination Considerations for Design (Section 2.8.3)

The pathway conclusions are based on the screening and evaluation of existing RPC data against RTs and CULs that were conducted in the Recontamination Assessment. Other chemical features, such as the presence of groundwater contaminant plumes, are also described.

2.8.1 Upland Pathway Conclusions Riverbank Erosion There are concentrations of RPCs in riverbank soil and shoreline sediment that exceed CULs and RTs (where available). As a result of the elevated concentrations and because of the bank stability requirements, the Recontamination Assessment Report concluded that riverbank areas adjacent to the nearshore SMAs should be evaluated as part of RD. It is expected that the remedy will be designed and implemented to stabilize erodible contamination in the riverbank adjacent to SMAs. EPA and DEQ will also be looking at the RIS&G riverbank to confirm the previous determination that the site represents a low recontamination concern (EPA, 2018c). In the fall of 2018, DEQ identified a failing retaining wall on the south side of the Stan Herman property as an additional potential source of recontamination that is not sufficiently assessed or controlled (Table 2-1). DEQ is reportedly

21 The four dioxin/furan RPCs are: 1,2,3,4,7,8-hexachlorodibenzofuran (HxCDF), PeCDD, PeCDF, and TCDD.


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working with ODOT to implement abatement measures to prevent migration of the wall fill material (asphalt grindings) to the river (Table 2-1).

In addition to these two ongoing riverbank source control evaluations, EPA collected data to evaluate riverbank conditions following the fire at the former warehouse on the Stan Herman property (Ecology and Environment, 2018). EPA and DEQ concluded that the riverbank at the Stan Herman property has been adequately stabilized with the placement of crushed rock during the emergency response action at the former warehouse and does not present a recontamination risk that would prevent the RM11E Group from moving forward with RD in the RM11E Project Area (EPA, 2018e). The RM11E Group evaluated the EPA data and identified RT and CUL exceedances in the unarmored riverbank soil (RM11E Group, 2018). The RM11E Group noted a lack of adequate soil data in the unarmored portions of the riverbank underneath and adjacent to the former warehouse to determine whether those areas may pose recontamination risk to the RM11E in-water remedy. Should active remediation that incorporates the shoreline downstream of RM 11.15 (e.g., near the former Stan Herman warehouse) be required, additional assessment of the shoreline conditions would be warranted during RD.

Groundwater Although concentrations of some RPCs in groundwater samples from nearshore wells exceed the associated CULs, the concentrations observed suggest that there is not an upland groundwater plume that would impact the design, construction, or effectiveness of an in-water RA under current conditions (GSI and DOF, 2018). The only relevant groundwater issue identified in the area is a dissolved-phase tetrachloroethylene (PCE) and trichloroethylene (TCE) plume from Tarr that discharges to the river between approximately RM 11.05 and RM 11.20, at levels that exceed groundwater CULs (Figure 2-27). The plume is being remediated and monitored under the DEQ Cleanup Program (Table 2-1) and is not expected to impact the sediment remedy.

Stormwater Extensive source control efforts have been undertaken to remove and/or control sources in most of the RM11E Project Area stormwater drainage basins. With the exception of the added SCMs and effectiveness monitoring requirements identified in Section 2.2 and Table 2-1, EPA and DEQ have concluded that the source control efforts have been effective and that the risk of recontamination to river sediments via stormwater discharge is low (DEQ, 2016). The Recontamination Assessment Report affirms that, with the exception of BEHP (which requires added SCMs and performance monitoring by Glacier NW and ODOT), the risk of recontamination by other RPCs is low. DEQ will continue to require ongoing stormwater monitoring through its industrial stormwater permits to confirm the effectiveness of source control actions, DEQ will require additional source control actions as needed.

2.8.2 In-Water Pathway Conclusions Upriver (i.e., Suspended Sediments in Surface Water) The Recontamination Assessment Report includes an evaluation and analysis of incoming settleable suspended sediment data collected upriver from 2007 and 2009. The incoming sediment concentrations from upriver are below RALs and are not a component of RD. As


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stated in Section 2.8.3, the CULs may be shown to not be achievable, or recontamination above CULs may occur over the long term in the RM11E Project Area, based on the results of the site-wide baseline and long-term monitoring results..

Incoming sediment concentrations for seven of the eight RPCs (i.e., total PCBs, PeCDD, TCDD, HxCDF, arsenic, BEHP, and TPH Diesel) into the RM11E Project Area exceeded the sediment CULs. These data were collected before the implementation of several RAs upriver of the RM11E Project Area and other upriver SCMs, indicating that upriver contributions to recontamination were present, but are currently uncertain in magnitude since the RAs have been implemented. As additional upriver information is collected, some of the COC concentrations associated with sediment transport into the RM11E Project Area may be shown to be naturally sourced background contaminants (e.g., arsenic) or watershed-level contaminants with concentrations that exceed currently established CULs. Thus, the CULs may not be achievable or recontamination may occur in the RM11E Project Area. EPA and DEQ have characterized the upriver sediment pathway as conditionally controlled, pending the site-wide baseline and long-term monitoring results (Table 2-1). Control of this potential source of recontamination lies within the jurisdiction and authority of DEQ.

Surface Sediment Resuspension Redistribution and mixing of surface sediments in the RM11E Project Area will continue to occur because of natural and anthropogenic scour. The Selected Remedy, described in the PHSS ROD, allows surface sediment with concentrations below RTs to remain in place, and contemplates that MNR will eventually result in reduction of contamination to CULs. Redistribution of surface sediments below applicable RTs is a component of the Selected Remedy rather than a source of recontamination. However, redistribution is expected to influence short-term and intermediate-term concentrations on the remediated surfaces.

Subsurface Sediment Exposure and Resuspension The Recontamination Assessment Report identifies areas with subsurface PCB contamination in the RM11E Project Area exceeding applicable RTs within and outside of the current SMA footprint. The scour potential from wave erosion, wake erosion, and propeller wash in this general area is moderate to high, indicating these areas could experience resuspension that could be a source of recontamination. There may be areas outside of the current SMA footprint where subsurface contamination may be subject to scour. The potential for scour and resuspension of subsurface sediments will need to be considered during the RD to prevent recontamination. It is expected that the remedy will be designed and implemented to limit exposure of buried sediment contamination or to remove the buried sediment contamination.

Advection of Groundwater through Contaminated Sediment (i.e., Porewater) The CapSim advection/dispersion model efforts, conducted as part of the Recontamination Assessment, demonstrated that expected PCBs and other hydrophobic organic compounds (HOCs) in the sediment can be reliably contained using a simple sand cover as a chemical isolation layer. The potential for sediment remedy recontamination via groundwater advection through contaminated sediment therefore can be controlled through a properly designed sediment cap. EPA and DEQ have characterized the in-water SMA porewater pathway as not sufficiently assessed or controlled, anticipating that refinements to the


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model and added evaluation in areas identified for capping will be conducted during RD (Table 2-1).

Existing Structures The recontamination potential from existing structures within the current SMAs is thought to be low given the inert and weathered nature of in-water materials. The pilings that supported the former warehouse on the Stan Herman property show evidence of creosote treatment and charring, and elevated dioxins and furans in riverbank soil were detected near those pilings. As such, there may be recontamination potential from the pilings at the Stan Herman property, but the potential has not been quantified. To the extent that pilings in the RM11E Project Area are expected to remain in place after RA, they will be assessed during RD to determine whether they are treated, and if so, whether additional action is warranted.

Overwater Activities Shoreline and upland facilities operate under best management practices (BMPs) and exhibit standard practices of care aimed at reducing inputs to stormwater or direct spills to the river. However, there are overwater activities that may impact surface water quality and localized sediment concentrations. For example, direct drainage from the Fremont Bridge is a potential source of RPCs (PCBs, arsenic, BEHP, and hydrocarbons) to the river within and beyond the RM11E Project Area and is considered by DEQ to pose a medium risk of recontamination to the river (DEQ, 2016). EPA and DEQ have indicated that additional stormwater SCMs are needed for Fremont Bridge scuppers and areas draining to outfall WR-306, and for performance monitoring (Table 2-1). Although future impacts from overwater activities have been reduced using BMPs, the potential for accidental releases, such as a potential oil spill, will continue to exist. In the absence of large, unpredictable releases, the contaminant input from the stormwater and overwater activities pathways is much lower than from upriver and poses a low potential for recontamination of surface sediments. Future spills or releases within the upland stormwater drainage basins and overwater areas are expected to be addressed by DEQ and appropriate authorities.

2.8.3 Recontamination Considerations for Design Although some of the recontamination pathways (e.g., upriver) are beyond the RM11E Group’s control, there are several pathways for which recontamination potential can be significantly reduced or eliminated through a properly designed remedy. These pathways include:

Riverbank erosion. Given the RT and/or CUL exceedances of focused COCs and/or RPCs and the need to address bank stability when evaluating remedial alternatives (Section 2.5.7), the riverbank conditions along most of the RM11E Project Area will be evaluated as part of RD studies. The remedy, as envisioned, will be designed and implemented to stabilize relevant banks adjacent to SMAs and limit exposure of any contaminated riverbank materials.

Exposure and resuspension of buried sediment contamination (i.e., subsurface sediment with concentrations that exceed applicable RTs). Areas with known buried sediment concentrations above RTs that are located outside of the SMAs will


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be further evaluated during the RD process to mitigate the potential of the material being exposed and/or evaluate removing this material to limit impacts to remedy effectiveness.

Advection of groundwater through contaminated sediment (i.e., porewater seepage). Areas with known sediment concentrations above RTs that are left in place and capped will be evaluated during RD to confirm cap effectiveness, or possibly to incorporate components (such as activated carbon) to mitigate recontamination and impacts to remedy effectiveness.

Potential leaching and abrasion from existing structures. To the extent that timber piles and/or the former crane tramway remain in place as part of the remedy, they will be assessed during RD to determine if they contain COCs that could be a source of recontamination or impacts to the remedy, and if so, whether additional action may be warranted.

The areas identified in the Recontamination Assessment Report (see Figure 8-1 of the Recontamination Assessment Report) for evaluation during RD have been refined in Section 8 of this BODR.

2.9 Site-Specific CSM Refinements for RD The CSM has progressed through various stages of the PHSS project, from initial site characterization to the RM11E-specific Recontamination Assessment Report as described below.

CSM RI/FS and ROD. The CSM developed for the PHSS RI/FS process (EPA, 2016a and 2016b) integrates the information gathered through extensive physical, chemical, and biological characterizations to provide a working understanding of current conditions, human health and ecological risks, and ongoing contaminant sources in PHSS. The RI/FS CSM addresses legacy sources and transport mechanisms on a PHSS-wide scale. Section 10 of the Final RI Report summarizes the site-wide CSM, describing it as a representation of the environmental system and the biological, physical, and chemical processes that affect the transport of contaminants from sources through environmental media to human and ecological receptors in the system (EPA, 2016a). Section 6.1 of the ROD states that the CSM is a tool that is used to communicate site conditions and support the decision-making progress. Figures 2 through 5 of the ROD (which are Figures 2-28a through 2-28d in this BODR) provide a visual schematic of the human health CSM, major elements of the CSM, physical CSM, and ecological CSM. EPA has determined that the Selected Remedy is protective of human health and the environment (EPA, 2017).

CSM RM11E Supplemental RI/FS Work Plan. A more specific CSM for the RM11E Project Area was presented in Section 4 of the RM11E Supplemental RI/FS Work Plan (Work Plan; GSI and DOF, 2013). Site characterization data gaps identified in the Work Plan were filled as described in the Field and Data Report (GSI, 2014). The updated data set combined with the final RTs presented in the PHSS ROD were used to update the SMAs (Section 2.7.1).


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CSM RM11E Recontamination Assessment. The CSM was refined in the Recontamination Assessment Report to focus on the physical pathways that have the potential to transport RPCs to the RM11E Project Area following remedy implementation (Figure 2-26, and Section 4 of the Recontamination Assessment Report). It also described the physical site setting (geologic, hydrologic, hydrogeologic, etc.) and the nature and extent of RPCs in various media. Contaminant fate and transport mechanisms were also discussed to support the recontamination pathway evaluations.

In this BODR, the CSM for RD for RM11E has been further refined to support development of design concepts and inform approaches to remedy implementation at RM11E. The elements of the CSM that were further evaluated and refined to support this BODR include: the chemical and physical conditions summarized in Section 2 and the design criteria that are summarized in Section 3. The primary design CSM components are tabulated in Figure 2-29 along with a conceptual cross section illustrating their applicability.

While the refined CSM and associated RD process focus on information needed to inform active remediation of SMAs, it is important to consider that the Selected Remedy allows for large areas where surface sediment concentrations exceed CULs to be left in place to naturally attenuate (i.e., MNR). During the attenuation period, sediment that remains in place with COC concentrations below RALs, but exceeding CULs, may be mobilized and some of this contaminated material may be deposited on the remediated sediment surface in the RM11E Project Area. This redistribution of contaminated sediment is a component of the Selected Remedy rather than a source of recontamination. The assessment of remedy effectiveness and recontamination will be determined during long-term monitoring to establish recovery rates and the eventual equilibrium concentrations in surface sediment over large areas extending well beyond SMA footprints. This assessment is typically evaluated by EPA during the 5-Year Review cycles.


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3. Design Criteria

EPA’s Remedial Design/Remedial Action Handbook (EPA, 1995) states that the design criteria for RD are the technical parameters and applicable or relevant and appropriate requirement (ARARs). The design criteria for active sediment remediation as well as the programmatic Selected Remedy at PHSS are set forth in the following sections of the ROD and summarized below:

Remediation Technologies (ROD 10.1.1)

River Regions (ROD 14.2)

ROD Technology Application Decision Tree (ROD Figure 28)

Institutional Controls (ROD 14.2.6)

Design Requirements (ROD 14.2.9)

Key ARARs (ROD 10.1.1.10)

This section includes identification of zoning, future land use considerations, and easement and access considerations for RD/RA. In addition, the ROD specifies that the site-specific final technology assignments are to be identified in RD to ensure that the final constructed remedy is appropriate for actual site conditions.

3.1 Remediation Technologies (ROD 10.1.1) The sediment remediation technologies included in the ROD—containment, in situ treatment, removal, disposal at offsite commercial landfills, ex situ treatment, ENR, and MNR—are described in this section. Design requirements for the active remediation technologies are summarized in Section 3.4.

3.1.1 Containment Containment technologies physically and chemically isolate impacted sediment to reduce unacceptable risks to human health and the environment. Five types of containment are described in the ROD:

Engineered Caps. Layers of materials—such as sand, gravel, and clay—are placed over the impacted sediment to isolate and prevent movement of contamination.

Armored Caps. The addition of erosive-resistant materials, such as large rocks, are placed over engineered caps to reduce the potential of erosion from river currents, prop wash, and wave action along the shoreline.

Reactive Caps. The addition of amendments, such as activated carbon or organoclay, to an engineered cap in cases where groundwater or porewater may release contaminants through the cap.


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Armored Reactive Caps. The addition of erosive-resistant materials, such as large rocks, are placed over reactive caps to reduce the potential of erosion from river currents, prop wash, and wave action along the shoreline.

Significantly Augmented Reactive Caps. Specific to areas where nonaqueous-phase liquid (NAPL) or PTW that cannot be reliably contained remains in the river, organoclay reactive layers in conjunction with low-permeable materials are incorporated into the cap design.

3.1.2 In Situ Treatment In situ treatment reduces contaminant concentrations, toxicity, bioavailability, and/or mobility while leaving contaminated PTW sediment in place. Treatment options include in situ solidification/stabilization and sequestration, and amendments to caps or residual layers, such as activated carbon or organoclay mats.

3.1.3 Removal Impacted sediment is removed from the river while submerged (dredging) or while exposed along the shoreline during low river stage (excavating). The removed material is transported to a transload facility where it is off-loaded and prepared for shipping and disposal at approved solid waste landfills. Transload facilities may be located at RM11E or at offsite third-party sites that will be identified and evaluated during RD. Following removal, a “residual sand layer” will be placed over the dredged/excavated area to cover the exposed surface and isolate dredge residuals.

3.1.4 Disposal at Offsite Commercial Landfills Material removed from the river will be disposed at offsite landfills22 (Resource Conservation and Recovery Act [RCRA] Subtitle C or D facilities). Disposal may require dewatering of the material and treatment of the water generated by the process. The material is transported to the disposal site(s) via land (truck or rail) and/or water (barges). The ROD states that Chemical Waste Management of the Northwest Landfill in Oregon and the Roosevelt Regional Landfill in Washington have sufficient capacity for the disposal of sediment expected to be removed from PHSS.

3.1.5 Ex Situ Treatment Ex situ treatment involves the use of chemical, physical, or biological technologies to transform, destroy, or immobilize contaminants. Ex situ treatment is not anticipated to be required for the materials removed from RM11E because those materials are not expected to contain RCRA hazardous wastes, pesticide residue, or manufactured gas plant (MGP) wastes (see Section 6.2.7).

3.1.6 Enhanced Natural Recovery In areas of the river where natural recovery is occurring, but not at a rate sufficient to reduce risks within an acceptable time frame, enhancement or acceleration of the recovery process can be accomplished by adding a thin layer of clean sand over the contaminated sediment.

22 DMM Scenario 2 – Offsite disposal is specified in the Selected Remedy, ROD Section 14.2.


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The ROD proposes this ENR technology only in the Swan Island Lagoon area of PHSS, and not in the RM11E Project Area.

3.1.7 Monitored Natural Recovery Outside of SMA areas at PHSS, CULs are expected to be achieved through MNR. As stated in the ROD’s glossary, MNR is a risk reduction approach for contaminated sediment that uses ongoing, naturally occurring processes to contain, destroy, or reduce the bioavailability or toxicity of contaminants in sediment. At PHSS, 1,774 acres of sediment are expected to naturally recover (ROD 14.2) over time primarily because of physical isolation of surface sediment through natural deposition of cleaner material coming in from upstream, along with dispersion and mixing.

3.2 River Regions (ROD 14.2) The ROD subdivided the site into river regions as a basis to assign remedial technologies within PHSS. Determining an appropriate technology to assign to each river region is dependent on area-specific characteristics and environmental conditions that include contaminant concentrations; current and reasonably anticipated future land and waterway use; areas of erosion/deposition; sediment bed slope; infrastructure, such as docks and piers; and physical sediment characteristics.

The ROD identified programmatic remedial technologies by river regions as a basis for identifying a presumptive Selected Remedy that is protective of human health and the environment. The ROD recognized that modifications to the programmatic remedial technologies may be necessary during design for each SMA to ensure that the final constructed remedy is appropriate for the actual site conditions23.

The river region definitions and the programmatic presumptive remedial technologies from the ROD are summarized below. Figure 3-1 shows the river regions associated with the RM11E Project Area. The Selected Remedy is also presented by river region in Figure 28 of the ROD (Figure 3-2 in this BODR).

Navigation Channel (ROD 14.2.1). The federally authorized Navigation Channel of the Willamette River as defined by Navigation Channel lines on the east and west sides of the river. The Lower Willamette River Navigation Channel currently operates at a depth of -40 ft CRD, with a proposed deepening to its authorized depth of -43 ft CRD (-38 ft NAVD88 at RM11E). The remedial technology considerations identified in the ROD for the Navigation Channel Region are summarized below:

o Dredge to avoid constructing a remedy (cap or residual layer) within the authorized dredge depth.

Dredge and cap if RT24 depth > authorized depth + buffer + cap thickness.

23 ROD Section 14.2, Post-ROD Data Gathering and Other Information Verification. 24 There is no PTW/NRC at RM11E. The RT represents the lower of the PTW and RAL.


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Dredge to RT followed by placement of a residual layer if RAL depth < authorized depth + buffer + cap.

PTW (NAPL/not reliably contained [NRC]): There is no PTW/NRC at RM11E.

o Coordinate with cleanup at the rest of the site to minimize recontamination. This cleanup may occur at the same time or later than other cleanup actions.

Future Maintenance Dredge (FMD) Areas (ROD 14.2.2). Locations in the river that are periodically dredged to allow continued marine activity, such as vessel movement, shipping, and docking. The remedial technology considerations identified in the ROD for the FMD Region are summarized below:

o Dredge to RALs or to depth required for placement of cap or backfill.

o Dredge and cap if RT depth > maintenance dredging depth + buffer + cap thickness. Cap should not interfere with maintenance dredge, including overdredge and buffer zone.

o Dredge to RT followed by placement of a residual layer if RAL depth < maintenance dredging depth + buffer + cap.

o PTW (NAPL/not reliably contained [NRC]): There is no PTW/NRC at RM11E.

o Cap should not interfere with maintenance dredge, including overdredge and buffer zone.

Intermediate (ROD 14.2.3). Outside of the horizontal limits of the Navigation Channel and FMD Regions to the riverbed elevation of approximately +3 ft NAVD88 (-2 ft CRD). The remedial technology considerations identified in the ROD for the Intermediate Region are summarized below:

o Consider and evaluate avoiding or minimizing impacts to the aquatic environment and floodway to meet Clean Water Act (CWA; Section 404) and federal floodway requirements as well as climate change impacts. The programmatic technologies were based on the following assumptions:

The elevation of the top of the cap or residual layer will be no higher than the pre-design elevation to avoid loss of submerged aquatic habitat, preserve slope stability, and negate adverse impacts to the floodway.

EPA estimates the dredging depth required to accommodate a cap will generally be 5 ft (the actual depth to be determined during RD).

o Dredge to depth to achieve RTs and remove PTW, or to a depth to allow placement of cap or backfill material.

o Place a residual layer, such as sand, after dredging.

o There is no PTW/NRC at RM11E.


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o Final elevation of dredge and capped areas will be considered such that the surface of the constructed remedy is appropriate for post-construction use.

o If appropriate to protect sensitive species, incorporate a habitat layer.

Shallow (ROD 14.2.4). Shoreward of the riverbed elevation of approximately +3 ft NAVD88 to the riverbank (+13 ft NAVD88). The remedial technology considerations identified in the ROD for the Shallow Region are summarized below:

o Consider and evaluate avoiding or minimizing impacts to the aquatic environment and floodway to meet CWA (Section 404) and federal floodway requirements as well as climate change impacts. The programmatic technologies were based on the following assumption:

The elevation of the top of the cap or residual layer will be no higher than the pre-design elevation to avoid loss of submerged aquatic habitat, preserve slope stability, and negate adverse impacts to the floodway.

o Dredge to achieve RT if less than 5 ft thick and backfill to grade.

o If depth of RT >5 ft, dredge 5 ft and place cap and backfill to grade.

o There is no PTW/NRC at RM11E.

o In the Shallow Region, a habitat layer (e.g., beach mix) will be used for the final layer of clean cover (i.e., residual layer) in both residual management areas and capped areas.

Riverbank (ROD 14.2.5). Shoreward of the Shallow Region (+13 ft NAVD88) to the top of bank. The remedial technology considerations identified in the ROD for the Riverbank Region are summarized below:

o Riverbanks are defined as areas from top of bank down to the river that may be contaminated along the shoreline next to contaminated in-river shallow areas. A more comprehensive definition of riverbanks will be provided in forthcoming guidance from EPA.

o Remediation of contaminated riverbanks is included in the Selected Remedy where needed to protect the remedy.

o For erosive deposits:

Excavate and/or cap or fill and cap.

Engineering caps or vegetation with beach mix will be placed as final cover based on area-specific design, which will account for appropriate slope according to the programmatic or site-specific Biological Opinion, as appropriate.

There is no PTW/NRC at RM11E.

o For non-erosive deposits – Conduct monitoring to demonstrate containment.


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The site-specific final technology assignments are to be identified in RD to ensure that the final constructed remedy is appropriate for actual site conditions25.

3.3 Institutional Controls (ROD 14.2.6) The ROD states that institutional controls (ICs) are intended to: (1) prevent or minimize exposure to humans, wildlife, and aquatic receptors to contaminated sediment and groundwater contained by an engineered cap or other cover at PHSS or left in place in the subsurface; (2) prevent or minimize human, wildlife, and aquatic exposure to contaminated fish and shellfish and to contaminated sediment and groundwater during construction of the Selected Remedy; and (3) maintain the integrity of the engineered components of the Selected Remedy.

ICs implemented to reduce human exposure to contaminated fish may include fish consumption advisories and community outreach and education. ICs used to prevent or minimize human exposure to contaminated fish, groundwater, sediment, and surface water may also include limiting land and waterway uses or activities on a short-term basis during implementation of the remedy and on a long-term basis after implementation of the remedy until remedial action objectives (RAOs) are achieved.

ICs used to protect caps or other covers may include limiting waterway and land use activities that may disturb or reduce a cap’s ability to contain the contaminated sediment or groundwater. Other types of controls for caps or areas with known subsurface contamination include coordinated permit reviews of in-river work. An Institutional Controls Implementation and Assurance Plan (ICIAP) for the RM11E Project Area will be developed during RD to set out the specifics of IC measures that will be proposed.

3.4 Design Requirements (ROD 14.2.9) The ROD sets forth design requirements for each category of active remediation and for remediation of riverbanks, as summarized below with reference made to the section of the ROD where additional detail can be found.

3.4.1 Capping Design (ROD 14.2.9.1) Caps are to be of sufficient thickness and materials to contain contamination remaining beneath the cap with sufficient armoring to remain in place when subjected to erosive forces from propeller wash, wind and vessel generated waves, and currents, including more frequent floods with higher peak flows expected from future climate change. Caps are to be designed to limit adverse effects on in-river and riparian habitat, including loss of shallow water habitat, to comply with the Endangered Species Act (ESA), and Section 404 of the CWA.

Cap design will also factor in appropriate earthquake design elements for contingency level events. As discussed in Section 3.7.1, cap design will be based on the low contingency-level earthquakes (CLEs) and caps will be included in a long-term operations and maintenance (O&M) plan for inspection and repair as needed following a seismic event.

25 ROD Section 14.2 Description of the Selected Remedy.


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Capping in the Navigation Channel and FMD Regions will consider the current and authorized channel depth, future navigation and maintenance dredging, and an appropriate buffer depth to ensure the integrity of the cap. Cap design will also consider the following design elements:

Capping - PTW (NAPL/NRC) 26 – Significantly Augmented Cap

o Include organoclay or other reactive material and/or low permeability material to reliably contain underlying contamination.

Capping - PTW (Highly Toxic)

o May require activated carbon or other reactive material as needed to meet RAOs.

Capping - Groundwater/Porewater Exceedance – Reactive Cap

o Require use of activated carbon or other reactive material. And/or low-permeability material to prevent contamination migration through the cap.

Capping - Structures

o Caps placed below or adjacent to structures.

o Consider logistics of placing capping material below structures, as well as consideration of structure maintenance.

o Consider physical constraints adjacent to structure:

Sediment bed slope

Current and future navigation uses

Propeller wash

o Minor structures (such as outfalls) moved to accommodate dredging and capping.

Capping - Debris

o Any debris that hinders expected performance of a cap will be removed before cap placement unless infeasible to remove.

Capping - Slope

o Cap designed to remain in place on slope.

Removal of material to lessen the slope angle.

Incorporate a buttress at the base of the slope to maintain stability and promote establishing habitats.

26 There is no PTW/NRC at RM11E.


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Consider innovative capping methods as appropriate.

Capping - Flood Rise and Navigation

o Avoid adverse impacts to floodway consistent with Executive Orders for Floodplain Management (11988 and 13690), Federal Emergency Management Agency (FEMA) regulations.

o Avoid adverse impacts to current and future navigation.

Capping - Land and In-River Use

o Caps designed to not be damaged or destroyed by anticipated uses.

Capping - Additional Requirements

o Coordination with National Marine Fisheries Service (NMFS) and U.S. Fish and Wildlife Service (USFWS) to comply with ARARs.

3.4.2 Dredging Design (ROD 14.2.9.2) Dredging designs will consider the lateral and vertical extent of contamination:

Lateral extent: based on SMAs.

Vertical extent: based on the Technology Application Decision Tree.

Dredging design will also consider the following elements:

Dredging - Residual Management

o Residual management cover (RMC) will be placed within the dredge prism and surrounding area to prevent exposure to residuals above CULs.

o Residual management layer – assumed to be 12 inches thick.

o Placed as soon as practicable following dredging.

o In the Navigation Channel, FMD, and Intermediate Regions – place sand to prevent exposure of residuals above CULs.

o In the Shallow Region – capping or backfilling to grade to prevent exposure above CULs and minimize adverse effects on in-river and riparian habitat, including loss of shallow water habitat.

Dredging - Structures

o Structures removed to access contaminated media unless:

Permanent (not floating or moveable).

Functional (not beyond design life and/or in disrepair).

Needed for current or future property and waterway use.


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o Minor structures, such as outfalls, will be moved when necessary to accommodate dredging.

Dredging - Debris

o Remove debris that limits access to contaminated media or reduces short-term effectiveness of dredging, unless technically infeasible to remove.

Dredging - Water Quality Controls

o Water quality controls, such as silt curtains, rigid containment (sheet pile walls), may be required to limit releases to water column from contaminated sediment, NAPL, debris, or other chemical or physical conditions to comply with water quality standards.

o Additional requirements from coordination with NMFS and USFWS to comply with ARARs.

Dredging – Disposal

o Dredged or excavated materials:

Tested to determine if treatment is necessary before disposal.

Tested to determine appropriate disposal locations.

o Disposal locations based on waste characterization and ARARs.

Dredging - Reactive Caps – Porewater

o Where dredging has been completed per RALs, more dredging may be necessary to accommodate reactive caps that may be required to meet cleanup goals in porewater.

3.4.3 In Situ Treatment Design (ROD 14.2.9.3) In situ treatment will be accomplished through the placement of a reactive layer of activated carbon in powdered or granular form.

Placement may be through broadcast placement of sand mixed with activated carbon or use of commercial product, such as AquaGate + PAC (or equivalent).

The concentration will be determined during RD, but must limit bioavailability sufficiently to meet the RAOs and CULs, and minimize the potential for adverse impacts to the benthic community and other aquatic organisms.

3.4.4 Enhanced Natural Recovery Design (ROD 14.2.9.4) The natural recovery process will be accelerated by adding a thin layer of clean sand over the contaminated sediment.

Placement of sufficient material, assumed to be 12 inches of sand or other appropriate benthic substrate, to meet the RAOs and CULs over time.


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Timing of the placement of ENR materials may be adjusted or sequenced to avoid undue acute impacts to the benthic environment.

3.4.5 Riverbanks (ROD 14.2.9.5) Contaminated riverbanks in an SMA will be remediated where they are contiguous with in-river contamination or where they pose a risk of recontamination to the remediation. These cleanups will be conducted in a manner that is compatible with the Selected Remedy and will minimize adverse impacts to riparian habitat including minimizing slope angle and the use of hardened banks to prevent erosion.

3.5 RA Performance Standards (ROD 14.2.10) The goal of RA performance standards and points of compliance (spatial and temporal) for sediment and riverbanks is to demonstrate that the remedy is functioning as intended. Short-term performance standards will be incorporated into the construction quality assurance plan and water quality monitoring plan in later stages of RD. Development of appropriate PHSS site-wide long-term spatial and temporal performance standards is outside the scope of the RM11E Group's AOC; however, such performance standards should be understood before final selection and implementation of an RA in the RM11E Project Area. Any performance standards finally developed will be adapted as appropriate during RD for conditions and RAs at in the RM11E Project Area.

Performance standards and associated short- and long-term monitoring are discussed in Section 7, including initial baseline and long-term monitoring concepts specific to the performance of the RM11E Project Area RAs. The initial monitoring concepts presented in this BODR will be further developed during RD and before initiating RAs.

3.6 Key ARARs (ROD 10.1.1.10) 3.6.1 Waste Designation Federal and state solid and hazardous waste regulations, such as RCRA, land disposal restrictions (LDRs), and the Toxic Substance Control Act (TSCA) impose requirements for handling, characterizing, treating, and the offsite disposal of dredged sediment and riverbank soil. Dredged or excavated materials will be tested to determine (1) whether treatment is necessary before disposal and (2) appropriate disposal locations.

3.6.2 Section 10 of the Rivers and Harbors Act Section 10 of the Rivers and Harbors Act of 1899 requires that regulated activities conducted below the OHW elevation of navigable waters of the United States not impede navigation. The Lower Willamette River Navigation Channel currently operates at a depth of -40 ft CRD with a proposed deepening to the authorized depth of -43 ft CRD (-38 ft NAVD88 at RM11E). Regulated activities include placement of structures, work involving dredging, disposal of dredged material, filling, excavation, or any other disturbance of soils/sediments or modification of a navigable waterway.


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3.6.3 Section 404 of the CWA Section 404 of the CWA requires that the discharge of dredge or fill material into waters of the United States avoid or minimize impacts to the aquatic environment. Unavoidable impacts could lead to the need for compensatory habitat mitigation as part of the Selected Remedy.

3.6.4 Section 401 of the CWA Under Section 401 of the CWA, a federal agency cannot authorize an activity that may result in a discharge to waters of the United States without ensuring that the discharge will comply with applicable state or tribal water quality standards. This is typically accomplished through issuance of a Section 401 certification by the state or tribe with delegated authority to establish water quality standards. The certification may include limitations or conditions as necessary to ensure compliance with water quality standards. For CERCLA cleanups, applicable water quality are ARARs with which EPA requires substantive compliance.

3.6.5 Endangered Species Act The ESA requires that federal action agencies (EPA in this case) ensure that the activities they approve do not jeopardize the continued existence of the listed species affected by action. The process will include formal consultations with the ESA agencies (USFWS and NMFS), either for the full PHSS project or on a site-specific basis. The result of the formal consultations will be either programmatic or site-specific Biological Opinions on the Selected Remedy that contain binding “reasonable and prudent measures” to minimize adverse potential effects on threatened or endangered species and designated critical habitat. These measures may include specific work timing, construction methods, and/or other measures that are not a major change to the remedy. The agencies will also consider the adequacy of the compensatory habitat mitigation proposed to comply with the substantive requirements of Section 404 of the CWA.

3.6.6 FEMA Floodplain Regulations The FEMA National Flood Insurance Program (NFIP) regulations require evaluation of encroachments that could result in any increase in flood levels during base (100-year) flood discharges. At RM11E, the Base Flood Elevation (BFE) is +32 ft NAVD88 (FEMA. 2004, FEMA. 2010). An engineering analysis, such as a Hydrologic Engineering Center River Analysis System (HEC-RAS), can be conducted to establish a no-rise condition. An alternative model or engineering analysis method may be used if calibrated to reproduce the Flood Insurance Study (FIS) profiles within 0.5 ft and meets the NFIP regulations. The ROD identified HEC-RAS modeling to ensure that flood rise management complies with regulatory requirements for both smaller and larger scales to assess the flood-rise impacts of the cleanup. Engineering analysis of pre- and post-project conditions is required to support the no-rise evaluation.

3.6.7 Standards for Surface Water and Groundwater Oregon Administrative Rules (OARs) promulgate numeric and narrative water quality standards to protect beneficial uses of groundwater (OAR 340-040-0020) and surface water (OAR 340-041-0340). In addition, CERCLA requires that a remedy attain the federal


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National Recommended Water Quality Criteria (NRWQC) that are protective of ecological receptors and human consumers of fish and shellfish if relevant and appropriate to the circumstances of the release of hazardous substances at the site [42 U.S.C. 9621(d)(2)(A)]. Chemical-specific ARAR numeric values are provided in Table 2.1-4 of the Portland Harbor Feasibility Study Report (EPA, 2016b) and include consideration of the following:

NRWQC27.

Oregon Water Quality Standards (WQS).

Oregon narrative water quality criteria.

Maximum contaminant levels (MCLs) and non-zero maximum contaminant level goals (MCLGs) established under authority of the federal Safe Drinking Water Act (SDWA).

Oregon Drinking Water Quality Act28 standards, or EPA regional screening levels (RSLs) for tap water when MCLs, MCLGs, and chemical-specific ARARs are not available.

Oregon Hazardous Substance Remedial Action Rules:

o OAR 340-122-0040(2)(a): Establishes acceptable risk levels for humans at 1 x 10-6 for individual carcinogens, 1 x 10-5 for multiple carcinogens, and a hazard index (HI) of 1 for noncarcinogens (EPA, 2017).

o OAR 340-122-0040(2)(c): For areas where hazardous substances occur naturally, the background level of the hazardous substances if higher than those levels specified in subsections (a), above. Note that EPA only established background concentrations for sediment and riverbank soils, and not for other media, including groundwater and surface water.

In addition to the chemical-specific ARARs, location-specific requirements and performance, design, or other action-specific requirements were also considered in the development of CULs. EPA selected the CULs presented in Table 17 of the ROD after evaluating concentrations protective of human health or the environment from the risk assessment, ARARs, and site-specific background values determined by EPA. Because background values were not determined for surface water and groundwater, the CULs for those media represent the lowest ARAR or risk-based value. Table 17 of the ROD indicates the basis for each number. Surface water and groundwater CULs are primarily based on ARARs that are protective of designated uses of the river and groundwater. The ROD states that application of MCLs and RSLs (if a contaminant has no MCL) is relevant and appropriate as CULs because a designated use of both groundwater and surface water as a drinking water resource and discharges of contaminants to the river from groundwater and porewater represent one continuous pathway (EPA, 2017).

27 The CULs for RAOs 3 and 4 are based on the lower of the federal NRWQC (organism + water) and Oregon WQSs (organism + water), MCLs, and non-zero MCLGs. 28 The Oregon drinking water standards match the national standards of SDWA.


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3.7 Seismic Considerations 3.7.1 Code-Based Seismic Design Considerations The ROD requires capping design to factor appropriate seismic design elements for CLEs. CLEs are defined in several design codes related to waterfront development, including in Section 3103F of the California State Lands Commission’s Marine Oil Terminal and Engineer and Maintenance (MOTEM) document and Chapter 2 of the American Society of Civil Engineers (ASCE) Document 61-14, Seismic Design of Piers and Wharves (ASCE 61-14; ASCE, 2014). Although ASCE 61-14 is tied to performance-based design of structures, its guidelines can be used to inform the level of seismic shaking considered for evaluating remediation alternatives in the RM11E Project Area.

The level of seismic shaking (i.e., peak ground acceleration, characteristic magnitude, and site-to-source distance) associated with the CLE is a function of the structure’s importance. According to ASCE 61-14:

High: Structures with a “high” design classification are essential to the region’s economy or post-event recovery, and should be designed for an earthquake with a 10 percent probability of exceedance in 50 years (i.e., an expected recurrence interval of 475 years). At RM11E, it is estimated to be a 7.4 magnitude event.

Moderate: Structures with a “moderate” design classification are considered to be of secondary importance to the regional economy and not essential to post-event recovery, and should be designed for an earthquake with a 20 percent probability of exceedance in 50 years (i.e., an earthquake with an expected recurrence interval of 224 years). At RM11E, it is estimated to be a 7.2 magnitude event.

Low: A third design classification, “low,” is established for structures that do not meet the “high” or “moderate” definitions, and does not require any special design considerations beyond meeting life safety requirements per the Oregon Structural Specialty Code (OSSC) and ASCE 7-16, Minimum Design Loads and Associated Criteria for Buildings and Other Structures (ASCE 7-16; ASCE, 2017).

By this ASCE 61-14 classification, the level of seismic shaking for capping would be based on the low CLE. Capped areas would be included in the long-term operations and management plan, including inspection and repair as needed following significant seismic events. EPA’s seismic recommendations for capping at the PHSS will be taken into consideration as RD continues to develop at RM11E.

3.7.2 Preliminary Liquefaction and Lateral Spreading Assessment According to regional seismic hazard maps (Mabey et al., 1997; Bauer et al., 2018), the soil adjacent to the Willamette River in the Portland area, including at the RM11E Project Area, is susceptible to liquefaction as a result of strong ground motions, such as those considered by the ASCE 61-14 “moderate” and “high” design classifications. Liquefaction is a process by which loose, saturated sand and non-plastic or low-plasticity silts, such as artificial fill and silty alluvium, temporarily lose strength during and immediately after a seismic event. At the RM11E Project Area, liquefaction is anticipated to result in ground surface settlement and lateral spreading toward the Willamette River. Conditions at the RM11E Project Area


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are not unique to PHSS, but are widespread along the lower Willamette River. If ground shaking consistent with a moderate or high CLE hazard level occurs, widespread liquefaction and lateral spreading should be anticipated throughout the PHSS along the banks of the lower Willamette River.

Further consideration of CLEs for capping design is on hold pending receipt of EPA seismic guidance for PHSS.

3.8 Zoning and Future Land Use The shoreline properties in the RM11E Project Area are zoned to preserve these areas for continued, active industrial use. See City of Portland Zoning Quarter Section Map No. 2829 (https://www.portlandmaps.com/bps/quarter-section/maps/?id=2829), attached as Figure 3-3. The specific zoning designations are listed below.

Industrial (indicated on zoning maps as “IH” for Heavy Industrial and “IG” for General Industrial). Shoreline properties in the RM11E Project Area are zoned Heavy Industrial except for the Cargill property, which is zoned General Industrial. These zoning designations implement the City’s land use plan to preserve an Industrial Sanctuary and encourage growth of industrial activities in the City. The Heavy Industrial zone designation protects:

“. . . areas where all kinds of industries may locate including those not desirable in other zones due to their objectionable impacts or appearance.” The development standards are the minimum necessary to assure safe, functional, efficient, and environmentally sound development (Portland City Code [PCC] 33.140.030.D).

General Industrial lands are also preserved for industrial uses and other uses are restricted to avoid conflicts (PCC 33.140.030.C).

Prime Industrial (indicated on zoning maps as “k”). All shoreline properties in the RM11E Project Area are zoned Prime Industrial. This is an overlay zone to prioritize industrial lands for long-term retention. These properties have (1) characteristics that are difficult to replace in the region and (2) limited ability to convert the land to other uses or reduce industrial development capacity (PCC 33.471.010).

River Industrial (indicated on zoning maps as “i”). All shoreline properties in the RM11E Project Area are zoned River Industrial. This is a greenway overlay zone to promote:

“. . . development of river-dependent and river related industries which strengthen the economic viability of Portland as a marine shipping and industrial harbor, while preserving and enhancing the riparian habitat and providing public access where practical.“ (PCC 33.440.030.A.4.)

Adjacent Zoning. The Fremont Bridge area, including the ODOT property associated with the bridge footings, is identified as a Scenic Resource (PCC


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33.480.020; indicated on the zoning map as “s”.) Several shoreline properties in the RM11E Project Area front River Street, which is designated as a major public trail (PCC 33.272.)

3.9 Easement and Access Requirements A component of RD is establishing easement and access requirements to do onsite investigations and RAs that primarily relate to the following:

Waterfront property/operations within the RM11E Project Area and adjacent uplands

Utilities in the RM11E Project Area (outfalls, submarine cables)

Oregon Department of State Lands (DSL; OAR 141-145) properties in the RM11E Project Area. The RM11E Group will engage DSL as part of the Alternatives Evaluation and 30% Design.


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4. Remedial Technology Screening

The purpose of remedial technology screening is to identify the portions of the RM11E SMAs where the site factors are compatible with the ROD technologies, and portions of the RM11E SMAs where further evaluation is required to develop technologies that would work better with the RM11E site factors.

4.1 ROD Technology Assignments The ROD identified programmatic technology assignments for the RM11E Project Area from the Technology Application Decision Tree (Figure 3-2). Figure 31e of the ROD depicts the conceptual technology assignments for RM11E that will be evaluated and refined during RD (Figure 4-1 in this BODR). The ROD assignments were refined for the BODR by mapping the site’s river regions and associated ROD technologies (Figure 3-1), overlain by the RM11E SMAs to provide an updated technology assignment map for the RM11E Project Area (Figure 4-2).

4.2 RM11E Site Factors The RM11E Project Area’s physical conditions and site activities that have been identified with a high potential to impact RD and implementation (“site factors”) (DOF et al., 2015) are listed below and described in detail in Section 2.5:

Facility Operations

Navigation Clearance

Construction Access

Submarine Cable Crossing

Groups of Vertical Pile Remnants

Large Undifferentiated Debris

Oversteepened Slopes

Structure Stability and Capacity

Vessel Propeller Wash

Wave Action

4.3 Remediation Technology Screening The conceptual ROD technology assignments for the RM11E Project Area are screened against the site factors to identify portions of the RM11E SMAs where the site factors are compatible with the ROD technologies, and portions of the RM11E SMAs where further


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evaluation is required to develop technologies that would work better with the RM11E site factors. While many of the site factors present challenges to RD at RM11E, five site factors stand out as significant constraints on implementing RD at RM11E without further evaluation: oversteepened slopes, facility operations, submarine cable crossing, groups of vertical pile remnants, and large undifferentiated debris.

4.3.1 Oversteepened Slopes As shown in Figure 2-14, much of the slope within the Intermediate, Shallow, and Riverbank Regions of the RM11E Project Area is classified as oversteepened by the geotechnical studies reported in the Implementability Study Report. The slope inclinations in those areas are steeper than what would be considered to be stable long term for the soils present. As detailed in the Implementability Study Report, dredging on the oversteepened slopes has the potential to destabilize and cause failure of the riverbanks. Conventional capping materials would not stay on oversteepened slopes.

The groups of vertical pile remnants found at Cargill are helping to stabilize the oversteepened slopes, similar to the application of pinch piles. Pinch piles are a geotechnical control measure to improve the stability of oversteepened slopes through the installation of closely spaced piling. The piles provide two benefits: the added shear strength of the pile material reinforces the slope against failure and improves the overall stability; and the installation of the piling densifies the soil on the slope, increasing the shear strength of the soil which also improves overall slope stability. While originally installed to support an over-water building, the closely spaced remnant piling at Cargill are now functioning to reinforce the oversteepened slopes. Additional evaluations regarding bank stabilization methods are necessary for both dredging and capping in the Intermediate, Shallow, and Riverbank Regions of the RM11E SMAs. Slope stability and the potential for sloughing in and adjacent to SMAs during dredging (RA as well as future navigational dredging) will be considered and evaluated when selecting appropriate, compatible technologies. These will consider conditions such as applying a cap adjacent to an area that will likely undergo future maintenance or navigational dredging. These, as well as other factors, will be developed further in design.

Updated topographic mapping of the Riverbank and Shallow Regions of the RM11E Project Area was recently conducted during low river stage to support an evaluation of the current bank stability as well as the likely impacts of bank stability from various RAs. This recently collected topography is included in the existing conditions base map (Figure 2-1), and for the cross sections (Sections 5 and 6) and other DOF design figures in this BODR.

4.3.2 Facility Operations As shown in Figure 2-11, three shipping terminals operate in the RM11E Project Area, from south to north: RIS&G (sand and gravel import by barge and export by truck), Glacier NW (cement import by ship and export by truck/rail), and Cargill (grain import by barge and truck, and export by ship). As detailed in the Implementability Study Report, the docks are busy year-round with more intense activity generally during the peak season of summer into fall.

The peak operational period for all three facilities corresponds with the July 1 through October 31 in-water work window. Implementing RAs in the FMD, Intermediate, Shallow,


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and Riverbank Regions at these facilities during the peak operational period would either involve repeatedly starting and stopping the remedy to avoid affecting facility operations and/or require shutting down facility operations, resulting in significant local and regional losses of jobs and revenue, both during RA and perhaps long-term as a result of the loss of customers to other providers.

Additional evaluations are required to investigate site access and alternate options for the timing of the RA implementation at the facilities in the FMD, Intermediate, Shallow, and Riverbank Regions in and around the main Cargill dock, Glacier NW docks, and RIS&G barge berth.

4.3.3 Submarine Cable Crossing PacifiCorp operates a submarine electrical cable crossing across the Willamette River to downtown Portland that passes through the RM11E Project Area between the Cargill and Glacier NW docks29. The estimated position of the cable is shown in Figure 2-11 along with a caution zone on either side of the estimated position. Although several attempts have been made to determine the depth of burial of the cables, it has not been precisely measured to date, but is estimated to range from inches to more than 6 ft beneath the sediment surface. The normal offset for any activity around the cables is 10 ft, which needs to be enlarged to account for the uncertainty of the actual location of buried cables.

4.3.4 Groups of Vertical Pile Remnants As shown in Figures 2-13a, 2-13b, and 2-13c, there are numerous remnant vertical timber piles around the Cargill terminal in an area of oversteepened slopes (see Section 4.3.1). The closely spaced remnant piles are likely stabilizing the existing banks. Removal of remnant piles may diminish slope stability and could result in slope failures. Removing closely-spaced piling on an over-steepened slope would have the opposite effect of pinch piling (see Section 4.3.1): removal of piling removes the shear strength provided by the piling and reduces the stability of the slope; and removal of the piling leaves voids in the slope with the surrounding soil displacing into the voids, reducing overall soil density which further reduces the stability of the slope. In situations where a slope is already oversteepened, such as in the vicinity of the Cargill Main Dock, removal of the existing closely spaced remnant piling would be expected to reduce the factor of safety against failure to unacceptable levels.

Groups of vertical pile remnants limit access for marine construction equipment, prevent a dredge bucket from achieving complete removal of target sediment, and complicate the placement of a cap by limiting the achievement of a uniform cap thickness.

Additional evaluations are required to determine viable remedial approaches at and around any groups of remnant piles, including consideration of removal, and to establish whether and to what degree, preservatives are present in any remaining piles. Future design documents will include appropriate evaluation of slope stability associated with remnant piling, including potential removal. Remnant piling are described in Section 5.3.5. Technology alternatives in Section 6 (see Exhibit 6-10) include consideration of dredging

29 The Level 3 Communications submarine fiber optic cable crossing is located under the southern edge of the Fremont Bridge. This is currently outside of the RM11E SMA.


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and capping around remnant piling, as well as pulling piling with associated bank layback, all of which will be the subject of design studies described in Section 8.

4.3.5 Large Undifferentiated Debris As shown in Figure 2-13a, large undifferentiated debris is expected along much of the slope in the Intermediate, Shallow, and Riverbank Regions of the RM11E Project Area, associated with historical operations and demolition of historical structures along the RM11E waterfront. Debris, such as concrete rubble, is evident in the Riverbank Region. Large debris is likely in the fill deposit in the RM11E Project Area as well as mantling the Shallow and Intermediate Regions of the shoreline. The presence of large undifferentiated debris can obstruct dredging operations. It can also be an impediment, or result in refusal, when attempting to drive soldier piles or sheet pile walls to contain capping material on oversteepened slopes.

Additional evaluations are required to determine the extent of large undifferentiated debris in areas under consideration for retaining wall construction and in proposed dredging areas.

4.3.6 Representative Project Cross Sections In addition to the area-wide evaluation of site factors discussed above, the RM11E ROD Technology Assignments are also compared to the site factors at representative cross sections; see Section 5.1.

4.4 Conclusion The remediation technology screening illustrates that, in most of the Navigation Channel Region, the technologies assigned in the ROD are implementable and can be carried through to RD. However, for the portion of the Navigation Channel in the proximity of the submarine cable crossing, and all other nearshore SMAs in the RM11E Project Area, further evaluation is required to identify implementable remediation technologies and approaches to constructing RAs (e.g., access and timing), and to ensure that they are appropriate for the actual site conditions. Figure 4-3 shows the portions of the RM11E SMAs where ROD-assigned technologies are consistent with site-specific factors, and areas where further evaluation is required.


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5. Remedial Technology Evaluation

Remedial technologies for the RM11E Project Area will be evaluated in three steps30:

Step 1: Cross Sections

Develop representative cross sections of site characteristics along the length of the RM11E Project Area.

Step 2: Facility Characteristics

Compile information on waterfront facilities along RM11E SMAs.

Identify technology attributes that are compatible with site facilities.

Step 3: Physical Compatibility

Compile information on RM11E Project Area physical characteristics.

Identify technology attributes that are compatible with RM11E Project Area physical characteristics.

The remedial technology evaluation also identifies project timing, including the potential for expanded in-water work windows and phasing the remediation over multiple years. The outcome of the remedial technology evaluation is the identification of technology attributes that are compatible with RM11E Project Area characteristics.

Section 6 identifies specific technologies that are compatible with facility and physical site characteristics for different representative portions of the RM11E Project Area (Step 4), evaluates the effectiveness of those technologies (Step 5), and evaluates their consistency with the ROD (Step 6).

5.1 Step 1: Cross Sections Cross sections have been prepared for representative locations along the RM11E waterfront. The cross sections extend from the top of bank into the Navigation Channel (Figure 5-1a) and are identified by the project mile (PM) stationing as follows:

PM 10.92: Sakrete (Figure 5-1b)

PM 11.02: Stan Herman (Figure 5-1c)

PM 11.12: RIS&G barge berth (Figure 5-1d)

PM 11.15: ODOT outfall WR-306 adjacent to RIS&G (Figure 5-1e)

PM 11.19: Glacier NW barge dock located between RIS&G and Glacier NW main dock (Figure 5-1f)

30 This is a refinement of the steps presented in the BODR Work Plan.


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PM 11.24: Open slope between Glacier NW barge dock and main dock (Figure 5-1g)

PM 11.31: Glacier NW main dock (Figure 5-1h)

PM 11.36: PacifiCorp submarine cable crossing between Glacier NW main dock and Cargill dock (Figure 5-1i)

PM 11.39: Former crane tramway, OF43, and remnant piling fields between Glacier NW main dock and Cargill main dock (Figure 5-1j)

PM 11.46: Mid-length of Cargill main dock (Figure 5-1k)

The cross sections show topography/bathymetry, river regions (as defined in the ROD), structures (including outfalls, docking facilities and underwater utilities), geologic units, stick logs (i.e., visual representations of PCB concentration by depth at the noted sediment surface grab and coring sample locations), and conceptual Target Material at each location as described below. Target Material, in this BODR, is surface and subsurface material that exceeds RTs.

5.1.1 Cross Section Features Topography/Bathymetry The riverbank and upland surfaces are based on the topographic mapping completed for the RM11E Project Area during the summer of 2018. The in-water bottom surface is based on bathymetric mapping completed by the Pre-RD Group in the spring of 2018. The topographic and bathymetric data sets were collected, processed, and merged by DEA. The vertical datum for the elevations on the cross sections is NAVD88. As shown in Figure 1-3, the average value of the conversion from NAVD88 to CRD in the RM11E Project Area is -5.3 ft (e.g., +13 ft NAVD88 is +7.7 ft CRD). Table 1-1 presents a summary of the elevation-related criteria appropriate for the RM11E Project Area.

River Regions The following river regions, defined in Section 3.2 of the ROD, are indicated on the cross sections:

Riverbank: Above elevation +13 ft NAVD88 to top of bank

Shallow: +3 to +13 ft NAVD88

Intermediate: Outside of the Navigation Channel and FMD Regions to +3 ft NAVD88

FMD (as applicable)

Navigation Channel

Structures Existing structures and remnant pilings are illustrated in the cross sections.

Geologic Units The following geologic units are indicated on the upland (left) side of the cross sections, as described in Section 2.7. The geologic unit by depth information is based on upland


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monitoring well borings, and therefore, may not accurately depict materials riverside of the well location or top of bank.

Artificial Fill

Silty Alluvium

Gravel Alluvium

Troutdale Sand

Troutdale Gravel

From the Shallow Region into the river—approximately 13 ft NAVD88 and below—geologic units are overlain by a sediment layer of variable thickness of recent alluvium that is not shown as a geologic unit on the cross sections (see Section 2.7 for more detail).

Stick Logs The existing sediment data31 (Section 2.7) provide a general indication of the nature and extent of the Target Material. The cross sections include stick logs of the sediment grab and core samples in the vicinity of the cross section (generally +/- 50 ft from the PM for each cross section) showing the measured PCB concentrations for the depth intervals of tested samples and the visual grain size description of the sample when available. PCBs were used on the cross sections to depict the extent of the conceptual Target Material because: (1) they are the predominant compound that exceeds RTs in the RM11E Project Area (Figure 2-23); (2) they are generally collocated with the other COCs that exceed RTs, and (3) PCBs are the most widely analyzed RT compound in the RM11E Project Area (Figures 2-17 through 2-22). The PCB concentration of each sample is color coded on the stick logs as follows:

Color Total PCB Concentration (ug/kg dry weight)

Red > 1,000

Orange > 750-1,000

Yellow > 500-750

Green > 200-500

Blue 75-200

White < 75

The nearshore RT for PCBs is 75 ug/kg dry weight (dw). All colors other than white within the nearshore stick logs indicate an exceedance of the nearshore RT. The PCB RT in the Navigation Channel is 200 ug/kg dw, which is based on the PTW concentration for PCBs. Exceedances of the RT in the Navigation Channel are represented by red, orange, yellow, and green.

31 Does not include analytical data from the Pre-Remedial Design Investigation and Baseline Sampling.


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Conceptual Target Material The cross sections show a conceptual representation of Target Material at each location to facilitate an initial evaluation of remedial technologies. This material is identified as conceptual Target Material to indicate that additional sediment sampling (surface and subsurface) will be required in several areas to gather sufficient additional horizontal and vertical data to refine the extent of Target Material for RD.

The PCB results presented in the stick logs were used as an indicator of the extent and thickness of Target Material for each cross section. The horizontal extent of Target Material presented in the cross sections is based on the surface sediment concentrations above the PCB RTs. The vertical extent of Target Material is based on depth and concentration data depicted in stick logs along or close to the cross section. In cases where there is not an existing core sample shown in the cross section, the thickness is based on a nearby core sample that is not close enough to show up on the cross section. The Target Material in the cross sections is shown with a uniform thickness around each core location; however, the actual Target Material thickness will likely be more variable and will be further refined during RD. In areas where the core did not determine the overall PCB DOI, a series of plus (+) signs are included along the base of the conceptual Target Material to indicate an unconfirmed DOI.

The color applied to the entire depth of the Target Material shown in a cross section is conservatively assigned the color associated with the highest PCB concentration observed at any depth interval within the associated stick log.

5.1.2 ROD Technology vs. Site Factors Section 2.5 describes 10 RM11E Project Area site factors that have a high potential to impact RD and implementation. Section 4.3 compares the site factors to the ROD technology assignments and demonstrates that, except for the Navigation Channel Region, further evaluation is required to develop technologies compatible with the site factors in all of the RM11E Project Area (i.e., in the Riverbank, Shallow, Intermediate, and/or FMD Regions of RM11E [Figure 4-3]). Section 4.3 identifies five significant site factors that are impediments to remedy implementation at RM11E: oversteepened slopes, ongoing facility operations, existing submarine cable crossing, groups of vertical pile remnants, and large undifferentiated debris.

Figures 5-2a through 5-2i provide a comparison of the remedial technologies identified in the ROD by river region to the site factors at each cross section that transects an SMA.32 A table in each figure indicates whether the ROD technology in a specific river region is compatible with each site factor (indicated by “C” in the matrix) or requires further evaluation (indicated by “X” in the matrix).

Multiple site-specific factors exist at most cross sections indicating that further evaluation is necessary to formulate appropriate technologies, as shown in the figures, and as summarized below:

32 No technology screening cross section is provided for the Stan Herman property area because there is currently no SMA located in the area (see Figures 2-23 and 5-1c).


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Cross Section PM 10.92, Sakrete (Figure 5-2a). The northern SMA offshore of Sakrete can be addressed by technologies that are compatible as assigned by the ROD. No further evaluation is required in this BODR.

Cross Section PM 11.14, RIS&G Barge Berth (Figure 5-2b). Facility operations, construction access, the potential for large undifferentiated debris, oversteepened slopes, and the presence of functional fixed structures require further evaluation to develop appropriate technologies for any remediation required in the Intermediate and FMD Regions.

Cross Section PM 11.15, ODOT Outfall (Figure 5-2c). Facility operations at the adjacent RIS&G facility and associated construction access, the potential for large undifferentiated debris, oversteepened slopes, and the presence of the outfall require further evaluation to develop appropriate technologies for any remediation required in the Shallow, Intermediate, and FMD Regions.

Cross Section PM 11.19, Glacier NW Barge Dock (Figure 5-2d). Facility operations, construction access, the potential for large undifferentiated debris, oversteepened slopes, and the presence of functional fixed structures require further evaluation to develop appropriate technologies for any remediation required in the Riverbank, Shallow, Intermediate, and FMD Regions.

Cross Section PM 11.24, Open Slope at Glacier NW Barge Dock to Main Dock (Figure 5-2e). Facility operations, construction access, the potential for large undifferentiated debris, and oversteepened slopes require further evaluation to develop appropriate technologies for any remediation required in the Riverbank, Shallow, Intermediate, and FMD Regions.

Cross Section PM 11.31, South End of Glacier NW Main Dock (Figure 5-2f). Facility operations, construction access, the potential for large undifferentiated debris, oversteepened slopes, and the presence of functional fixed structures require further evaluation to develop appropriate technologies for any remediation required in the Riverbank, Shallow, Intermediate, and FMD Regions.

Cross Section PM 11.36, Open Slope at PacifiCorp Cable Crossing (Figure 5-2g). The submarine electrical cable crossing, facility operations, construction access, the potential for large undifferentiated debris, oversteepened slopes, and the presence of a functional in-water dolphin and other shoreline fixed structures require further evaluation to develop appropriate technologies for any remediation required in the Riverbank, Shallow, Intermediate, FMD, and Navigation Channel Regions.

Cross Section PM 11.39, Former Crane Tramway, Outfall 43 (Figure 5-2h). Facility operations, construction access, pile remnants, the potential for large undifferentiated debris, oversteepened slopes, the presence of a former crane tramway, and a large outfall structure require further evaluation to develop appropriate technologies for any remediation required in the Riverbank, Shallow, Intermediate, and FMD Regions.


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Cross Section PM 11.46, Mid-Length of Cargill Dock (Figure 5-2i). Facility operations, construction access, pile remnants, the potential for large undifferentiated debris, oversteepened slopes, and the presence of functional fixed structures (including existing retaining walls in the riverbank) require further evaluation to develop appropriate technologies for any remediation required in the Riverbank, Shallow, Intermediate, and FMD Regions.33

5.2 Step 2: Facility Characteristics Facility operations have been identified as one of the primary site factors that pose a significant impediment to implementing RAs at RM11E. The 2015 Implementability Study Report compiled information on the facilities at Sakrete, Stan Herman property, ODOT, RIS&G, Glacier NW, Unkeles, and Cargill, where available. That information is summarized in Appendix A and is a source of information for this BODR. Topics compiled from the 2015 Implementability Study Report include:

Upland Ownership and Operations

Overwater and In-Water Operations

Facility Location

Existing and Planned Future Waterfront Operations

Waterfront Operations Vessel Information

Waterfront Operations Seasonality

Maintenance Dredging

Shoreline Modifications

Additional information on waterfront facility operations was gathered in 2018 for this BODR. Site visits and interviews were conducted with management and operations personnel at Cargill, Glacier NW, and RIS&G. Interviews were also conducted with the City regarding its outfalls and with PacifiCorp regarding its submarine electrical cable crossing. ODOT provided a written response regarding outfall WR-306 and the east abutment of the Fremont Bridge (provided in Appendix B). The 2018 interviews, site visits, and written responses focused on the following facility factors:

Development Plans. Future possible or planned development, maintenance, or upgrade plans, for both upland and in-water portions of the facility as they may relate to RD and RAs.

Access. Upland and in-water site access considerations at the facility during design studies and RAs.

33 The cross section at PM 11.46 represents general conditions along the mid-length of the Cargill main dock. PM 11.46 was not found to contain Target Material, as shown in Figure 5-1k, and does not pass through the presumptive PCB SMA (see Figure 2-23), while adjacent areas along the Cargill main dock (PM 11.44 and 11.48) are within the presumptive PCB SMA; therefore, Target Material in this area is shown for concept development only. The actual extent of the SMA at the Cargill main dock will be refined during RD.


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Operations. Facility operations and schedules in relation to the implementation of RAs, including discussion of potential interruptions of facility operations during remediation, the business impacts of such interruptions, and options for limiting operational interruptions and business impacts.

Upland Bank Stabilization. Future possible or planned upland bank stabilization or restoration programs at the facility as they may relate to RM11E RD and RAs.

Schedule. Seasonal and long-term operations and development schedules at the facility that may indicate the optimal timing of RAs at each waterfront facility.

Integration. Opportunities to integrate RAs with operations or development plans at the facility that could improve the outcome of both actions.

The information collected since the Implementability Study was drafted is presented in Appendix B and summarized below.

5.2.1 Development Plans There are no significant future development plans, aside from normal maintenance activities, scheduled to be conducted for the marine terminals or major utilities (i.e., City outfalls and PacifiCorp’s submarine electrical cable crossing) in the RM11E Project Area. ODOT has plans for upgrades at the Fremont Bridge; however, the area beneath and near the bridge is not currently within an SMA.

Cargill, Glacier NW, and RIS&G

o Cargill, Glacier NW, and RIS&G do not have current plans to remove, remodel, or change their waterfront marine terminals outside of repair or maintenance activities as necessary.

o Cargill has a permit to repair and or replace piles in its dock and dolphins.

o Although not yet planned, future changes to the waterfront marine terminals at Cargill, Glacier NW, and/or RIS&G are possible.

o Cargill and Glacier NW perform periodic berth dredging and expect to eventually deepen the ship berths in front of their facilities to match the Navigation Channel when the channel is deepened and maintained to the authorized depth of -38 ft NAVD88 (-43 ft CRD).

City and PacifiCorp

o There are no current plans to modify the major utilities along the waterfront (City outfalls and PacifiCorp submarine electrical cable crossing), although future changes are possible.

ODOT

o The Fremont Bridge will undergo seismic upgrades that will increase the size of its shoreline piers by 50 percent. ODOT has not provided the RM11E Group with plans or a timeline for the seismic upgrades.


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5.2.2 Access Access to the RM11E waterfront marine facilities and adjacent uplands for active sediment remediation is generally infeasible when the facilities are in operation and have vessels at the terminals for several reasons:

Oceangoing vessels moored at the docks and their associated mooring lines occupy the full extent of the docks and beyond because of their size, and would block access to marine construction barges during the RA.

The associated loading/offloading of oceangoing vessels at the adjacent upland terminals would constrain upland-based RAs behind the docks along the shoreline and, because of security requirements, access to these areas would require the consent of each independent vessel captain.

General safety protocol requires that divers not work around major vessels at a dock unless those vessels undertake specific “lockout/tagout” practices and procedures designed to safeguard divers from the unexpected energization or startup of machinery and equipment (OSHA 29 Code of Federal Regulations [CFR] 1910.147). Lockout/tagout is not a standard operational approach during loading/offloading operations and would require the consent of independent vessel captains.

It is not feasible to conduct RA work along the waterfront area between the Cargill main dock and the Glacier NW main dock during peak grain shipping and cement receiving periods because the presence of vessels at both docks would restrict access.

Limited access to the shoreline from the upland facility operations areas is available year-round at the northern ends of the Glacier NW, Cargill, and RIS&G facilities. Access to the shoreline from the rest of the upland facility operations areas is not available during operations. The Glacier NW, Cargill, and RIS&G facilities operate year-round at varying activity levels (e.g., peak season, off-peak season) that are described in Section 5.2.3.

5.2.3 Operations The 2018 site visits and interviews reaffirmed the operational information developed and presented in the 2015 Implementability Study Report (Appendix A). The following summarizes the information regarding facility operations:

RIS&G

o Sand and gravel are imported to the facility by flat deck material barges, typically between 100 and 200 ft long by 40 to 60 ft wide, with a loaded draft between 10 and 15 ft. The peak season for the facility is July through October when it operates at full capacity to support the regional construction industry with aggregate products.

o Material barges arrive every 3 days for offloading at its dock. Operations at the site are normally performed Monday through Friday from 12 a.m. to 3 p.m.

o There may be other facilities in the area that RIS&G could temporarily relocate its operations to should that be necessary to provide access for remediation.


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Glacier NW

o Cement arrives at the Glacier NW dock on Handysize34 and Handymax35 class vessels. Glacier NW’s peak season is July through October and aligns with the construction season in direct response to West Coast demand for cement.

o During peak season, four to five vessels moor and unload at the main dock per month. Vessel arrival dates and times are dictated by weather, conditions at sea, and decisions made solely by the independent vessel operators, and as such, are beyond Glacier NW’s control. It takes 5 to 7 days to unload cement from each vessel (adverse weather can extend offload time).

o Cement is shipped offsite from the upland terminal 6 to 7 days per week by truck and rail during peak demand. Trucking and rail operations normally operate from 2 a.m. to 6 p.m.

o The pneumatic Docksider™ located at the main dock that is used to offload cement from moored vessels is currently operating at the practical limit of its reach, so altering the configuration of the dock or berth to accommodate a cap supporting toe wall (see Section 5.3.2) (i.e., moving the fender piles a few ft from the face of the dock) is not feasible.

o Moored vessels currently occupy the entire distance between the face of the dock and the boundary of the Navigation Channel. Any reconfiguration of the dock or berth that encroached on the berthing area would result in ships interfering with the Navigation Channel.

o The terminal cannot be shut down without significant adverse employment and economic impacts because of the specialized nature of the facility’s operations (see Appendix B).

o No identified alternate marine terminal offloading locations or temporary cement storage facilities (domes or silos) are currently available to Glacier NW.

o December through February are off-peak months with less frequent activity at the Glacier NW terminal.

PacifiCorp

o Seven submarine cables provide electricity to northwest Portland and cross through the RM11E Project Area from a cable vault on the Unkeles property to the west side of the river. The cables are in continuous operation with no opportunity to interrupt transmission without interrupting power delivery to portions of downtown Portland.

o Dredging is not possible in the vicinity of the electrical cable crossing because of safety restrictions and cable integrity concerns.

34 Typical dimensions for a Handysize ship are: 590-foot length, 93-foot beam width, and 33.5-foot design draft. 35 Typical dimensions for a Handymax ship are: 600-foot length, 106-foot beam width, and 36.5-foot design draft.


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o Capping is not possible over the electrical cable crossing because of possible impacts to cable integrity. The placement of cap material would increase the load over the cables and cause consolidation of bed materials, resulting in added stresses along the length of the cables that could potentially lead to failure of the cables. Because the current condition of the buried cables cannot be determined, it is not possible to readily determine what level of added stress would cause damage and/or failure of the cables.

o The cables are in an area of high erosion potential and the weight of any necessary armoring may prevent capping over the cables. However, RD will consider any appropriate thin capping technology that may be identified or necessary.

o As directed by EPA, PacifiCorp is evaluating the feasibility of relocating the cables to facilitate remediation.

Cargill

o Grain is exported from the main dock on Handymax and Panamax36 class vessels. Operations at the grain terminal are normally performed during day shifts, while vessels remain at the dock around the clock until loaded.

o The grain terminal operates at its highest capacity in July through April—Cargill’s peak season—which coincides with the time-sensitive grain harvest and the busy export period thereafter.

o Vessel arrivals are scheduled in variable 15- to 30-day windows, but their actual arrival dates and times are dictated by weather, conditions at sea, and decisions made solely by the independent vessel operators, and as such, are beyond Cargill’s control.

o Moored vessels currently occupy the entire distance between the face of the dock and the boundary of the Navigation Channel, so any reconfiguration of the dock or berth that encroached on the berthing area would result in ships interfering with the Navigation Channel.

o During slower seasons at the terminal, vessels typically remain longer at the dock because of increased loading time.

o The terminal cannot be shut down without significant adverse employment and economic impacts because of the specialized nature of the facility’s operations (see Appendix B).

o There are currently no locations to which Cargill could shift all of its terminal operations during any shut down.

36 Typical dimensions for a Panamax ship: 740-foot length, 106-foot beam width, 39.5-foot design draft.


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o The upland grain terminal facilities provide services (including truck unloading) and sell product (including particular variants of wheat) unique in the geographic region.

o While Cargill’s barge dock is located immediately upriver, but just outside the RM11E Project Area, tugs and barges accessing the barge dock may traverse the RM11E Project Area or may be impacted by RM11E Project Area remedial activity.

City

o The City maintains three active outfalls at RM11E: OF45 at the northern end of the Stan Herman property, OF44 at the northern end of the Glacier NW property, and OF43 under the former crane tramway at the northern end of the Cargill property.

o There are no plans for changes to OF44 or OF45.

o Flow from OF44A, which is near the 12-inch-diameter OF44, was diverted into the City’s Eastside Big Pipe, and the former outfall was abandoned and filled with concrete several years ago.

o OF43 is an older 56-inch-diameter brick pipe storm sewer that conveys stormwater from an approximate 14-acre drainage basin in the Albina area; it also serves as an overflow for the City’s Eastside Big Pipe CSO a few times per year during peak rainfall events. The outfall is fully functioning and is not scheduled for replacement.

o The outfalls will also will be addressed during the alternatives evaluation and 30% Design as needed to implement the remedy, with details provided in the 60% Design.

5.2.4 Upland Bank Stabilization Based on the 2018 interviews, no future upland bank stabilization or restoration programs are planned at the facilities. However, concerns were identified with bank stability that may impact the RD/RA:

RIS&G

o The main berthing area is composed of an Eco-Block concrete gravity wall with driven steel pile for added stabilization. RAs at the base of the wall, if necessary, would require potential stabilization of the wall depending on the scope of the remedial construction.

ODOT

o There is visible evidence of a failed block wall surrounding ODOT’s outfall WR-306. ODOT indicated that it has no plans to stabilize the wall or outfall. Remedial construction near WR-306 could cause ground movement, further failure of the block wall, and damage to the pipe. It may be necessary to repair the slope at


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WR-306 before remediation to avoid damage to the existing outfall from ground movement during remediation. ODOT holds a 10-foot-wide permanent easement for the outfall across the Glacier NW property.

Glacier NW

o Remnant pilings and lagging walls along the shallow/bank area have signs of distress and failure as visibly evidenced by bank sloughing.

o The upland bank is oversteepened along much of the shoreline and has visible evidence of bank failure.

o A retaining wall constructed of stacked concrete blocks at the north end of the Glacier NW property at the ODOT outfall WR-306, and adjacent to the now-closed City OF44A, has failed. See ODOT above for further discussion.

Cargill

o Remnant pilings along the Cargill waterfront serve to stabilize the existing oversteepened slopes; removal (i.e., pulling them out) of pilings in the oversteepened portions of slopes would increase bank instability.

o Behind the Cargill main dock, soldier piles and tie backs imbedded in the shoreline and riverbank provide bank stability, which could be affected by, or limit RA options.

City

o Remedial construction near City OF43 (older brick pipe), including removal of the former crane tramway, could cause ground movement and damage to the pipe. It may be necessary to replace OF43 before remediation to avoid damage to the existing brick-laid pipe from ground movement during remediation.

5.2.5 Schedule The Glacier NW and Cargill facilities operate at full capacity during the current in-water construction window and no feasible opportunity has been identified to geographically shift operations to other facilities. If remediation in the general vicinity of, behind, or between the main docks at Glacier NW or Cargill must be conducted entirely within the primary Willamette River in-water construction window (July through October) it will either require repeatedly starting and stopping of remediation to accommodate facility operations and/or will exacerbate interference with facility operations during their peak season, resulting in adverse employment and economic impacts due to the specialized nature of the facilities’ operations and the significant volume of product imported into or exported from their respective terminals (see Appendix B). RIS&G indicated that it might be able to temporarily shift operations during remediation, but with some resulting potential impact to the supply of asphalt mix to the local market.

The off-peak season for Glacier NW is December through February and for Cargill is May and June.


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The City indicated that overflow events from the Eastside Big Pipe to OF43 might occur during major storm events. The potential for impacts of overflow events on RA will be addressed as part of RD.

As outlined in Section 5.2.3, the eastern portion of PacifiCorp’s submarine electrical cable crossing is located within an RM11E SMA. RM11E design engineers and PacifiCorp electrical engineers have concluded that capping or dredging near the energized cables is not technically feasible. Accordingly, any schedule for remediation at RM11E must take into consideration the relocation of the cable crossing, if feasible, as further discussed in Section 5.2.6.

ODOT has not yet scheduled its planned seismic upgrades to the Fremont Bridge.

5.2.6 Integration Opportunities to integrate RAs with facility operations were discussed in the 2018 interviews along with consideration of development plans (if any) that could be integrated with RAs in a manner that could improve the outcome of both actions. While no specific development plans were identified, the facilities did provide input on integration of RAs with operations (see additional discussion in Section 8). The Alternatives Evaluation will provide specific details on business operations and the balancing of those operations with potential interruption in order to complete the RA.

RIS&G

o RIS&G indicates that it is willing to accommodate remediation at its site, as required.

o The company has a dredging division and is familiar with the timing and phasing of such work.

Glacier NW

o It may be possible to complete sediment remediation in the area north of Glacier NW’s main dock, which is used to offload cement from vessels, including the area around the northern barge dock, during the normal in-water construction window. The tie-up bollards in this area may need to be relocated closer to the main dock for vessel stabilization.

o Remediation at Glacier NW’s main dock during the off-peak December to February time frame, while maximizing upland cement storage, could possibly provide 2- to 3-week windows with no ship activity.

o The main dock consists of two concrete sections: a north section and a south section. Removing the south section of the main dock could afford access to that section of the main dock and provide a means for remediation at and around the main dock. Under such a scenario, Glacier NW could temporarily shift all cement offload operations from the south section to the north section of the main dock. The removed south section of the main dock either could be reconstructed north of the existing north section, essentially centering the main dock on the property, or could be rebuilt in its current location.


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Cargill

o Absent the development of expanded grain receiving capabilities at a different regional Cargill terminal, no opportunities to integrate remediation with existing or planned operations or development have been identified. Several alternatives for facilitating remediation at the Cargill terminal will be evaluated in the next stage of RD.

o Also, while Cargill has no plans to remove the former crane tramway near the north end of the property, the company indicated that removal of the former crane tramway could be considered if appropriate to complete remediation at that location.

PacifiCorp o PacifiCorp’s submarine electrical cable crossing has been identified by the

RM11E design engineers as a site factor that has a high potential to impact if, how, and when contaminated sediment in the area can be remediated.

o To accommodate the requirements for remediation of the RM11E Area as provided for in the ROD, and as directed by EPA in its comments on the Implementability Study Report, PacifiCorp is currently evaluating multiple technical solutions to de-energize (i.e., relocate) the cables in submarine electrical cable crossing while maintaining uninterrupted service to the downtown core.

o An initial feasibility study completed by a PacifiCorp multidisciplinary project team in June 2018 indicated that the best technical option to provide an alternate route for power is to construct a new distribution river crossing deep beneath the Willamette River using horizontal directional drilling (HDD) technology before beginning any in-river remediation activities near the current cable crossing.

o Initial review of planned activities and a preliminary critical path schedule indicate the project duration required to execute this technical solution ranges from 3 to 4 years. This schedule is highly dependent on permitting, technical evaluation of subsurface geology, acquisition of real estate, and the time required for qualified contractors to meet the technical specifications of the project, all of which could result in additional time to completion.

o PacifiCorp will conduct this project in phases that include scope refinement, detailed design, construction, and distribution system commissioning. There will be multiple check-in points along the way, including a final feasibility determination planned for early 2020.

o Year One of the project will focus on scope refinement and design. These efforts, anticipated to be complete in early 2020, will include the collection of geotechnical samples along the preferred new alignment path(s) in the Willamette River to determine the geotechnical profile and inform the technical specifications for the HDD contractor.

o Year Two of the project will include the final feasibility determination, and, if the project is feasible, contract negotiation and execution.


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o Years Three and Four of the project will include an optional second round of geotechnical sampling, construction and commissioning of the new HDD crossing, and de-energization of the existing cables.

o Removal of the de-energized cables as necessary for dredging and/or capping should be integrated with RA.

o Given the complexity of the cable relocation project, the project schedule has the potential to extend to 5 years, which would further impact the timing of RA in this area.

City

o The City is evaluating alternative locations or methods to protect OF43 as part of RD. Preliminary evaluations indicate that the outfall could be relocated likely at the same elevation vertically, but at an adjacent lateral location, so that the RA can be completed without interruption of outfall function.

5.2.7 Other RM11E Facilities Unkeles, Stan Herman, and Sakrete are discussed in the Implementability Report. That information is summarized in Appendix A. Coordination with DSL and the fiber optic cable crossing will be performed during RD with the development of the remediation plan.

5.2.8 Technology Attributes Compatible with Facility Factors The following are the primary facility factors that influence remedial technology feasibility at RM11E:

Berth Deepening. Cargill and Glacier NW expect to eventually deepen the ship berths in front of their facilities to match the Navigation Channel when the channel is deepened and maintained to the authorized depth of -38 ft NAVD88 (-43 ft CRD). The design of RA dredging depths to remove impacted sediment should accommodate the future deepening of the Navigation Channel, vessel approach areas, and berths at the main Cargill and Glacier NW docks to -38 ft NAVD88 (-43 ft CRD). The design of capping systems over impacted sediment, particularly on the slopes behind the face of docks and adjacent navigation areas, should also accommodate the future deepening.

Facility Operations. Cargill, Glacier NW, and RIS&G operate marine terminals with year-round loading/offloading at waterfront docks. The primary in-water construction window (July through October) coincides with the peak operation periods at these facilities. Limiting remediation to the primary in-water construction window will either require repeatedly starting and stopping remediation to accommodate facility operations and/or will substantially increase adverse economic impacts. Performing the RA at these areas in off-peak season windows outside of the current in-water construction window could reduce economic impacts, and facilitate more efficient RA.

Bank Stability. Bank stability issues identified at Cargill (removal of remnant pilings, integrity of existing soldier pile wall), Glacier NW (failing slopes and walls,


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and oversteepened riverbank), RIS&G (Eco-Block gravity wall), the City (OF43 brick pipe), and ODOT (failing wall around outfall WR-306) could worsen as a result of adjacent RAs.

Submarine Electrical Cable Crossing. As long as the PacifiCorp electrical cable crossing remains energized, dredging and capping are not feasible because of safety and cable integrity concerns.

Remedial technologies compatible with the facility factors at RM11E will consider:

Designing dredging and capping to accommodate deepening of the Navigation Channel, vessel approach areas, and berths at the Cargill and Glacier NW main docks to -38 ft NAVD88 (-43 ft CRD).

Completing RAs during an expanded fish window (July through February) to limit operational impacts during peak operations at the main docks at Cargill and Glacier NW, in a manner that limits impacts to fish.

Avoiding pulling of remnant pilings.

Improving the stability of the failing slopes at Glacier NW.

Stabilizing or replacing OF43 such that drainage service is not interrupted and to avoid damage to the outfall from the RAs at the site.

Providing temporary and/or permanent shoring as required for remediation adjacent to the RIS&G Eco-Block gravity wall and ODOT block wall.

Removing the PacifiCorp submarine electrical cable crossing from service at RM11E (i.e., relocating crossing before RA).

5.3 Step 3: Physical Compatibility Five physical characteristics of the site were evaluated to assess their effect on the implementability of various remedial technologies: sediment, slopes, riverbanks, structures/utilities, and debris.

5.3.1 Sediment Existing information regarding the nature and extent of sediment contamination is presented in Section 2.7 and summarized herein. Additional surface and subsurface sediment sampling will be necessary to finalize mapping of the horizontal and vertical extent of Target Material to support design of dredging and capping, and will be performed during RD.

Prior sediment sampling and analysis at RM11E has characterized Target Material. Focused COC data in surface and subsurface sediments are summarized in Table 2-6 and Table 2-7, including highlights denoting which samples contain material that exceeds RTs (i.e., Target Material). Target Material is mostly loose and soft sediment comprising a wide range of grain sizes, including silty clay with some sand, clayey or sandy silt, clean or silty sand, gravel, or other combinations. In many cases, finer sediment has in-filled the void space in dense gravels at the surface. Section 2.4.3 presents a summary of physical sediment data


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with the available general physical characteristics (e.g., grain size, bulk density, water content, and plasticity).

Target Material generally mantles the underlying geologic units at the site (see Section 2.4.2). The underlying geologic units include: artificial fill of variable density with known building debris; silt/sand, which is soft to medium stiff silt, and loose to medium dense sand; and the underlying gravel and lower sand units, which are medium dense to very dense.

The influence of Target Material and the geologic units on active remediation is presented below.

Dredging of Target Material Because of its loose character, Target Material will likely offer limited resistance and relative ease of removal by dredging using lightweight buckets. However, as discussed below, the presence of various types of debris in Target Material may necessitate the use of stronger buckets (heavier digging buckets, or hydraulic closing buckets deployed from excavators) to achieve removal. The stronger buckets will also be more effective in penetrating into the underlying geologic units (dense sands and gravels) as needed to complete removal of Target Material.

Environmental dredging buckets (i.e., closed top clamshell buckets) can be used to remove Target Material and to dig into the underlying geologic units. Specific remediation dredging methods (RDMs) (see Section 6.1.5) will be considered for use during a proposed extended in-water work window to further limit resuspension, turbidity, and residuals as appropriate for the Target Material and site conditions at RM11E.

Dewatering of Dredged Target Material Dredging captures both sediment and water, and tends to entrain water into the dredged material, increasing its water content above in situ conditions. Dredging with an enclosed bucket captures more water than traditional open-top buckets. The water and sediment are placed in the material barge and as the sediment settles in the barge, or further settles at a transload facility, water is produced that results in the accumulation of sediment-laden—or turbid—water. While water associated with dredged sand clarifies rapidly, water associated with dredged silty and clayey material (i.e., anticipated RM11E Target Material) will tend to remain turbid for longer periods of time, possibly days. Consequently, free-standing water that is removed from sediment barges or drains from stockpiled sediment at transload facilities may require processing to reduce turbidity and associated COCs before being discharged back to the river (see Section 6.1.6).

Caps/Residual Layers over Target Material The technical feasibility of constructing caps and residual layers is largely dependent on the thickness and physical characteristics of the near-surface sediment and on the thickness and nature of the constructed cap layers. While residual layers tend to be no more than 1 foot thick, caps can be several ft thick, especially when erosion-resistant layers are incorporated into the cap. Very soft sediment may not support direct placement of the full thickness of a cap without significant disturbance and/or displacement, while more dense material, such as the site geologic units, can receive capping materials with little disturbance.


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Target Material is geotechnically classified as soft fine-grained material (silts and clays) and loose granular materials (sand and gravel). The technology for placing caps on such material on a relatively level riverbed is well developed and proven. Depending on site-specific conditions, it can involve broadcasting granular capping/cover material over the surface of the water to deliver an initial blanket of material on the riverbed, followed by placement of subsequent layers (or “lifts”) to build up the cap to the final thickness. The thickness of the lifts will be dependent on site-specific sediment type and strength, and can range from initial lift thicknesses of less than 1 foot to achieve gradual pore-pressure dissipation, with subsequent lifts increasing in thickness as settling of the underlying sediment is achieved.

Placement of a cap on loose and soft Target Material will result in some consolidation of the underlying Target Material. The amount of consolidation will depend on the thickness of the cap and the geotechnical properties of the underlying Target Material. Further evaluation to determine lift thicknesses, sequencing, and potential consolidation for capping of specific areas of the RM11E Project Area will be conducted during RD. Challenges associated with capping on the inclined riverbeds of RM11E are discussed in Section 5.3.2.

Placement of granular capping/cover material through the water column will result in short-term increases of turbidity, even if the material is washed to remove fine-grained material. Because cap/cover material will, to the extent practicable, be selected to meet CULs, the turbidity does not pose the same level of exposure as does turbidity associated with the removal of contaminated sediment (see Section 6.2.6).

5.3.2 Slopes Figure 2-14 provides a map of oversteepened slopes (slopes steeper than 2H:1V) at RM11E, including both riverbank and sediment areas from the Implementability Study Report. The following sections address the design challenges associated with implementing capping or dredging on slopes, including oversteepened slopes.

SMA Slopes SMA slopes are slopes that are inside SMA boundaries. Most SMA slopes at and around the Cargill and Glacier NW main docks and barge docks are classified as oversteepened. In their current condition, these slopes are marginally stable and could experience slope failure with little disturbance or added loads. RAs that include capping or dredging on or near oversteepened slopes could result in slope failure unless appropriate measures are incorporated to address slope instability. Additionally, on slopes found to be stable where Target Material comprises thin layers of relatively low level COCs, alternative cover measures, such as ENR or in situ treatments, will be considered. The viability of alternative cover measures will be determined following collection of Phase 1 RD data and developed through 30% Design.

Riverbank Slopes Data from the 2018 topographic survey shows that much of the riverbank along RM11E is oversteepened (e.g., the Glacier NW property has slopes steeper than 2H:1V with some slopes steeper than 1H:1V). The oversteepened wedge of material at the top of the riverbank is susceptible to failure during remedial construction, such as dredging or capping at the adjacent SMA, and thus would compromise the RA. For the purpose of this BODR, it is


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assumed that the oversteepened wedge at the top of the riverbank will be flattened or otherwise stabilized as part of remediation before initiating capping or dredging in the adjacent SMA.

Dredging on Slopes All construction activities on oversteepened slopes, (e.g., dredging, capping, installing shoring, pulling remnant piling) have the potential to further destabilize the slopes. Dredging on SMA slopes will need to be completed in a manner that mitigates the potential for failure of the oversteepened slopes. The effectiveness of dredging on oversteepened slopes will be addressed during the alternatives evaluation and refined as part of the 60% Design considering the following: :

Removing or stabilizing the wedge of oversteepened material at the top of the riverbank before initiating dredging on the slope.

Sequencing the removal of Target Material from the top of the slope toward the bottom of the slope.

Implementing stair-step dredge cuts for steeper slopes to reduce sloughing of sediment.

Using an articulated fixed-arm dredge (excavator) with precision positioning of the bucket for improved bucket control and reduced sediment disturbance on steeper slopes.

Providing shoring where needed to maintain slope stability.

Capping on Slopes Almost all the areas under consideration for capping at the RM11E Project Area, according to the ROD Technology Application Decision Tree, are located on the shoreline slopes, the majority of which are oversteepened. Geotechnical evaluations completed for the Implementability Study Report established that slopes steeper than 2H:1V in fill material are oversteepened and have a low factor of safety. Slopes in the Silty Alluvium are considered oversteepened when greater than 2H:1V to 2.5H:1V and in the Gravel Alluvium when greater than 1.5H:1V.

The consideration of capping on slopes is based on the following preliminary design parameters:

2H:1V Capping Slope. Capping material placed on slopes will have a final surface slope no steeper than 2H:1V for general stability.

Dredge Elevation of -38 ft NAVD88. To maintain compatibility with future authorized dredging of the Navigation Channel, capping and slope stabilization will not constrain future deepening to -38 ft NAVD88 (-43 ft CRD) at the Cargill and Glacier NW main docks or at the associated vessel approach areas (FMD Region).

Armored Caps. Caps constructed on RM11E slopes to the top of the wave zone at elevation +23 ft NAVD88 will be armored to protect against potential erosion from waves and propeller wash.


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The constructability and effectiveness of several slope stabilization methods are addressed below:

Toe Buttresses. A toe buttress is typically a dike of riprap material located parallel to and at the base/toe of a slope to retain capping material or erosion protection placed on the slope. Without the toe buttress, the material placed on the slope may fail or slide down the slope. At RM11E terminals, the toe of the slope is typically also in line with the face of the main docks. As shown in Figure 5-3a, where the toe of the slope is at the face of the dock, a toe buttress would extend into the berth at the dock thereby encroaching on the navigational clearance required by ocean-going ships that call on the facility. In the same manner, a toe buttress constructed at the toe of a slope upstream or downstream of a dock could also extend into the navigation path of a vessel approaching or leaving a dock. Consequently, toe buttresses are not a viable means for constructing shoreline caps in portions of the RM11E Project Area, such as where the toe of the slope is at the face of the dock or adjacent to areas of active terminals.

Toe Walls. An alternate approach to toe buttresses can be construction of vertical cantilevered37 walls at the toe of the slope, either at the face of a dock or along an adjacent slope. An example of a toe wall is presented in Figure 5-3b. To retain an armored cap with a backslope of 2H:1V and provide for berthing in front of the toe wall to -38 ft NAVD88 (-43 ft CRD), the wall would need to be approximately 20+ ft high. The application of toe walls constructed at the face of marine terminals at the toe of an underwater slope was investigated. A maximum constructed exposed height of 10 feet for cantilevered sheet pile walls was found at the Port of Seattle, and a maximum of 14 feet exposed height for a combination soldier pile / sheet pile wall was found, also at the Port of Seattle. Factors that influence practical toe wall height include soil conditions, back slope orientation, the presence and character of existing structures, site seismicity and earthquake induced ground motion and lateral spreading. The practical limit of underwater cantilevered walls with a 2H:1V backslope is considered to be approximately 10 to 15 ft; consequently, toe walls are not currently considered a viable and/or cost-effective means for constructing shoreline caps at the RM11E marine terminals.

Slope Flattening. Oversteepened slope conditions can be remedied by flattening the slope, either by moving the toe of the slope farther into the river and placing fill at a more gradual slope, or by laying the slope back into the adjacent upland. As is the case for toe walls in some portions of the RM11E Project Area, such as at active deep water berths, extending the toe of the slope farther into the river would encroach on the navigational clearance required for ocean-going ships that call on the facilities. Alternatively, laying back the entire slope into the adjacent upland may be impeded by shoreline buildings and other structures, and could result in considerable loss of industrial waterfront property and impair ongoing facility operations and road access. Laying back only a portion of the slope may be viable in some situations.

37 While tied-back walls provide a means to construct taller upland walls, installation of tie-backs under water is currently not a viable technology.


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Hybrid Methods. Hybrid methods of constructing caps on RM11E slopes, including consideration of slope stability, will be investigated during RD. Examples include, but are not limited to:

o Articulated Concrete Block (ACB) Mats. ACB mats provide an erosion-resistant overlay on a slope through an interlocking matrix of concrete blocks connected by a series of cables that pass through the blocks. ACB mats are normally anchored into a trench at the top of the slope. The mats can also be anchored to a row of soldier piles at the top of the slope. ACB mats can be prefabricated with precast concrete blocks or can be cast in place by pumping grout into quilted fabric forms (e.g., marine mattresses). The RD evaluation of ACB mats would include consideration of the added application of activated carbon in areas of porewater concern.

o Remnant Piling Systems. Hundreds of remnant timber pilings exist around the Cargill facility, many from the prior Irving terminal. Pulling such remnant pilings from oversteepened slopes is problematic because doing so would reduce the stability of the already oversteepened slopes. One concept to be investigated during RD, assuming good integrity of the submerged pilings, would be to span the distance between adjacent pilings at the same elevation with 1- to 3-ft-high structural members to create a series of parallel walls up the slope. Those walls would be used to retain capping material placed over the slope.

AquaGate. AquaGate® is an example of an available in situ treatment technology that can be directly placed on the sediment surface and incorporates activated carbon to reduce the bioavailability of organic compounds. Placing AquaGate on RM11E slopes, including consideration of slope stability, will be investigated during RD. While not a “cap,” it is intended to reduce the need for capping in certain situations. AquaGate consists of gravel coated with powdered activated carbon (PAC). The material falls to the river bed because of the density of the gravel. Over time the PAC is released from the gravel and incorporated into the surface sediment. Ongoing studies for a pilot application of AquaGate on slopes beneath docks at the Puget Sound Naval Shipyard in Bremerton, Washington, are demonstrating considerable reductions in bioavailability of PCBs (ESTCP, 2017). AquaGate and other similar products are an example of technologies to be considered during RD to reduce bioavailability of COCs for areas not readily addressed with dredging or capping.

Seismic considerations for capping are addressed in Sections 2.4.1 and 3.7.

5.3.3 Riverbanks As shown in Figures 2-16c through 2-16e and Table 2-6, multiple surface soil samples have been collected along the riverbank of the Cargill and Glacier NW properties that had RT exceedances. DEQ concluded that there is a low potential for recontamination from riverbank erosion (DEQ, 2016); however, the riverbank will be further evaluated as part of RD because of bank stability issues. As part of that evaluation, riverbank soil with RT exceedances that has the potential to erode into the river and contribute contamination to SMAs during or following RA will be identified for in-place containment or removal during


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RA, as determined appropriate and with consideration of limiting impacts to riparian and shallow water habitat.

5.3.4 Structures/Utilities Several existing structures and utilities are located in the RM11E Project Area. Performing remedial activities within the vicinity of structures and/or utilities, whether placing caps or dredging, can affect their integrity and operational viability.

Structures Structures in the RM11E Project Area include docks, walkways, dolphins, and retaining walls; as well as buildings, silos, and storage facilities in the adjacent uplands. The integrity of those structures can be sensitive to changes in soil loading conditions that result from dredging or capping activities near them. A qualitative structural assessment was completed for most structures at Sakrete, the Stan Herman property, ODOT, RIS&G, Glacier NW, and Cargill and is summarized in the Implementability Study Report. The assessment included a structural analysis of the axial and lateral loading capacity of the pilings and an analysis of the general stability of retaining walls. The qualitative structural risk assessment ranked the potential for structural damage in connection with two conceptual dredging scenarios and one conceptual capping scenario as: “high risk,” “moderate risk,” “low risk,” or “not applicable.” The following summarizes the primary mechanisms of concern and the structures identified as “high risk” for damage from the three conceptual RAs, should they be implemented near the structures:

Dredging Concept 1. Dredging depth of up to 5 ft near waterfront structures and slopes.

o Primary Mechanisms of Concern. Removal of material riverward of a dock or dolphin pilings that may affect the stability and load carrying capacity of piles; and the potential for slope failure from dredging, particularly in areas with oversteepened slopes.

o High Risk. Concrete bulkhead wall at RIS&G. To mitigate potential damage, capping vs. dredging alternatives near structures will be evaluated during RD, along with the potential need for temporary/permanent shoring and/or work area offsets.

Dredging Concept 2. Dredging depth of 5 to 10 ft near waterfront structures and slopes.

o Primary Mechanisms of Concern. Similar to those for dredging up to 5 ft with higher potential for an abrupt failure.

o High Risk. Pilings at the Sakrete dock and building; pilings and former building at the Stan Herman property; ODOT bridge foundation; RIS&G dolphin pilings and concrete bulkhead wall; Glacier NW pilings at the barge dock, main dock, dolphins, walkways, cement storage dome, and silos; Unkeles retaining wall; and Cargill pilings supporting the main dock, barge dock, dolphins, ship loader towers, walkways, soldier pile wall, buried concrete shaft wall, abandoned pier, silos, and buildings. To mitigate potential damage, capping vs. dredging alternatives near structures will be


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evaluated during RD, along with the potential need for temporary/permanent shoring and/or work area offsets.

Capping Concept. Capping up to 3 ft thick near structures.

o Primary Mechanisms of Concern. Added “down-drag” loads on pilings; and induced bank instability on oversteepened slopes that could adversely impact or undermine adjacent upland buildings and structures.

o High Risk. Sakrete buildings; ODOT bridge; RIS&G silos; Glacier NW cement storage dome and silos; and Cargill silos and buildings. Potential pilings and slope stability impacts will be evaluated in RD, where capping is considered a viable RA within the RM11E SMA.

Utilities

Utilities are discussed in Section 5.2.

Removal/Relocation of Structures The 2018 interviews identified the potential for removal (temporary or permanent) of the following facilities, if appropriate for RA. Note that the removal and replacement of utilities is addressed above.

Stan Herman. The building at the property was demolished after a fire in 2018. Only the former building’s timber pilings remain on the site. The owner has not identified future plans for the property.

ODOT. The agency plans to make seismic upgrades to the Fremont Bridge, including increasing the size of the shoreline piers by 50 percent. The bridge piers are not in the currently defined SMA at RM11E.

RIS&G. The company indicated that it may be able to temporarily relocate its barge operations to facilitate remediation around its dock. RIS&G also indicated that a permanent upgrade of its existing concrete bulkhead wall might be needed depending on the nature of remediation adjacent to the wall.

Glacier NW. The company indicated that removing the south section of the main dock to provide access to sediment currently under and behind that section of the main dock could be considered to facilitate remediation. Under such a scenario, Glacier NW could perform cement offloading from the north section of the main dock. The removed south section could be reconstructed north of the existing north section, essentially centering the main dock on the property or rebuilt in its current location. The reconstruction would be in conjunction with or following remediation along the northern portion of Glacier NW property.

Cargill. The company indicated that removal of the former crane tramway near the north end of the property could be considered if appropriate to complete remediation at that location. The City’s aging brick pipe OF43 is also located in the footprint of the former crane tramway and would likely be damaged during demolition. Cargill has also indicated that removal and subsequent replacement of its main dock, while not currently anticipated, could be evaluated if needed to reasonably implement remediation at and behind the dock.


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5.3.5 Debris Three categories of debris were identified in the Implementability Study Report: individual large debris, groups of vertical pile remnants, and undifferentiated debris (Figure 2-13a). The impact of each type of debris on constructability of caps and dredging is discussed below.

Individual Large Debris This debris class consists of individual pieces of large debris or clusters of large debris scattered on the riverbed. Examples of individual large debris include sunken logs and pilings lying on the riverbed. Previous multi-beam surveys have identified that there are more than 100 pieces of large debris at the site. Additionally, a considerable amount of rock and broken concrete has been placed along the RM11E shoreline in the wave zone.

Large debris can be detrimental to RAs. While installing a cap or placing cover material, large debris can breach the layers and preclude placement of sufficient cap or cover material. During dredging actions, large debris can obstruct access to Target Material, and prevent a dredging bucket from fully closing. Loss of sediment from the unclosed bucket can increase resuspension/turbidity, and in turn increase the potential for generated residuals on the riverbed. Additionally, large debris that is embedded into oversteepened slopes can reduce slope stability if removed.

Targeted removal of large debris can reduce impediments to dredging and facilitate more effective placement of caps and covers. In some instances, a thin blanket of sand can be placed over an area before removing large debris to mitigate resuspension of soft, fine-grained contaminated sediment during debris removal. Thin sand blankets were placed over a dredge cut face during the Head of Hylebos sediment remediation. The appropriateness of the placement of a sand blanket and other remediation techniques will be further considered during 60% Design.

Groups of Vertical Pile Remnants Groups of remnant timber pilings cover approximately 1.4 acres of the RM11E Project Area, with the highest density of pilings located along the oversteepened slopes near the Cargill docks (Figure 2-13b). Standing piles can prevent access for floating remedial construction equipment. Groups of remnant pilings may interfere with consistent placement of cover material over the Target Material during capping actions. During dredging, the closely placed pilings will interfere with the dredge bucket, limiting or preventing access to the sediment, and potentially result in incomplete removal of Target Material around and between pilings.

A typical management action for remnant pilings is to remove them before implementing an RA. In the RM11E Project Area, pulling of the remnant groups of pilings (i.e., complete removal) is not advised because it would further destabilize existing oversteepened slopes. An alternate management action would be to cut the pilings at, or near, the mudline before implementing an RA.

Capping alternatives in the area of remnant vertical pilings will be investigated during RD. As discussed in Section 5.3.2, hybrid capping or covering options may be appropriate in areas of remnant pilings, and will be further developed in RD.


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The presence of remnant piling stubs after they are cut at the mudline will obstruct mechanical dredging. A Target Material removal option for those areas could be inclusion of diver-operated hydraulic dredging; however, the viability of diver-implemented removal will be limited by the combination of the large extent of pilings, the low productivity of diver operations, the operational constraints of the terminals, and the limited in-water construction window.

The options for addressing the residual piling will be addressed during the Alternatives Evaluation and 30% Design, including limiting preferential pathways through the cap.

Undifferentiated Debris Undifferentiated debris is material on or buried below the riverbed including surficial debris that is too small to be detected by hydrographic surveys (unlike individual large debris). It is anticipated to be found along the extent of the RM11E Project Area shoreline (Figure 2-13a) associated with historical shoreline structures that have since been demolished. Undifferentiated debris is expected to consist of rubble, concrete, asphalt, chains, stumps, logs, and other industrial and demolition debris. As with individual large debris, undifferentiated debris can prevent a dredging bucket from fully closing. Loss of sediment from the unclosed bucket can increase resuspension/turbidity, and in turn increase the potential for generated residuals on the riverbed.

Undifferentiated debris is not expected to be a significant impediment to placement of caps or covers as it is generally buried or not large enough to significantly distort a cap or cover.

Management actions to address undifferentiated debris in areas to be dredged could include added site characterization (e.g., borings, sub-bottom profiling) to better define the extent of the material, and inclusion of contingency actions to be developed during RD and implement during RA to address spikes in turbidity from debris removal.

5.3.6 Technology Attributes Compatible with Physical Characteristics The following is a summary of the primary physical characteristics that influence remedial technologies at RM11E, followed by a summary of technologies that are compatible with those physical characteristics.

Physical characteristics:

o Sediment. Much of the Target Material is composed of fine-grained silts and clays, which when disturbed can generate turbidity, release COCs into the water column, and result in residual contamination on the post-dredge surface.

o Riverbank slopes. Oversteepened riverbanks above the SMA could fail during or after remedial construction.

o Oversteepened SMA slopes. Much of the RM11E SMA has oversteepened slopes. In their current condition, these slopes are marginally stable and could fail with little added disturbance during or after remedial construction.

o Dock face. The main dock faces at Cargill and Glacier NW are at the toe of oversteepened slopes, which provides limited flexibility or room to construct cap retention structures.


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o Structures. Numerous structures in the RM11E Project Area have been identified as having a high risk of damage depending on the nature and extent of adjacent capping or dredging.

o Debris. Individual large debris can impede sufficient thickness of cap or cover material during placement. Removal of individual and undifferentiated debris can result in increased generation of turbidity and dredging residuals, as well as reduce the stability of oversteepened slopes.

o Remnant pilings. Groups of vertical pile remnants can obstruct the effective removal of Target Material and interfere with the consistent placement of cover material between and around the piles.

Remedial technologies compatible with the physical characteristics in the RM11E Project Area will consider the following:

o Flattening or otherwise stabilizing the oversteepened riverbank slopes before initiating remedial construction in adjacent SMAs, including slopes showing evidence of bank failure at Glacier NW and the failing wall around ODOT’s outfall WR-306.

o Sequencing dredging on oversteepened SMA slopes from the top of the slope toward the bottom of the slope, making stair-step bucket cuts using an articulated fixed-arm dredge with precision positioning to reduce sediment disturbance.

o Using hybrid cap or cover systems for addressing Target Material in areas where it is not feasible to construct a toe buttress or toe wall for capping, particularly behind a dock or adjacent navigation areas.

o Stabilizing structures where RAs pose a high risk of causing them damage, or selecting remedial technologies that do not put structures at an elevated risk of damage, including possibly temporary removal and replacement.

o Removing individual large debris from the riverbed before initiating dredging or capping. Developing contingency actions during RD to address spikes in turbidity during debris removal.

o Incorporating remnant pilings into RAs to preserve slope stability rather than pulling them.

o Applying ENR covers or in situ treatment layers over thin deposits of surface sediments that exceed RTs and in areas where neither capping nor dredging is practical.

o Evaluating new technologies that have yet to be identified that may be more compatible with the site conditions.

o Incorporating future dock repairs and/or facility construction into remediation plans.


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6. Site-Specific Remedial Approach

Development of a site-specific remedial approach for the RM11E Project Area is based on the following three steps:

Step 4: Compatible Technologies

Identify remedial technologies that appear to be compatible with the RM11E Project Area site factors and physical conditions. The site factors identified in Section 5 and shown on Figure 5-2a-5-2i will be considered during the engineering design studies, Alternatives Evaluation, and 30% Design as described in Section 8.

Step 5: Effectiveness

Describe the extent to which the identified technologies comply with environmental performance factors.

Step 6: ROD Consistency

Confirm consistency of identified technologies with the ROD design criteria.

6.1 Step 4: Compatible Technologies The intended outcome of this BODR, as stated in the Work Plan, was to identify site-specific remedial approaches that would be carried forward into RD. Based on an evaluation of the RM11E Project Area site factors and physical conditions, it is not possible to select definite site-specific remediation plans for all portions of the RM11E Project Area at this time. Additional design studies and regulatory decisions are necessary to address the significant site-specific structural engineering, facility operation, and access issues before making final technology determinations for portions of the RM11E Project Area (see Figure 5-2a-i).

This BODR has identified remedial technologies that appear to be compatible with the site conditions, including multiple potential technologies in some areas. The technologies will be further evaluated through design studies and developed in RD (see Sections 8 and 9), and are described in this section at each of the following locations within the RM11E Project Area:

Northern SMA offshore of Sakrete (PM 10.92)

RIS&G dock (PM 11.14)

ODOT outfall WR-306 (PM 11.15)

Glacier NW barge dock located between RIS&G and Glacier NW main dock (PM 11.19)

Open slope between Glacier NW barge dock and main dock (PM 11.24)

Glacier NW main dock (PM 11.31)


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PacifiCorp submarine electrical cable crossing between Glacier NW main dock and Cargill main dock (PM 11.36)

Cargill former crane tramway, OF43, and remnant piling fields in the open slope between Glacier NW main dock and Cargill main dock (PM 11.39)

Mid-length of Cargill main dock (PM 11.46)

Early engagement with NOAA and EPA concurrently would aid in the development of preferred alternatives.

6.1.1 Northern SMA Offshore of Sakrete (PM 10.92) The ROD technology assignments in the vicinity of PM 10.92 are shown in Figure 5-2a and summarized in Exhibit 6-1.

Exhibit 6-1. ROD Technology Assignment by River Region, PM 10.92 Riverbank Not Applicable – No SMA in adjacent River Region Shallow Not Applicable – No SMA in River Region Intermediate Dredge FMD Not Applicable – No FMD area Nav. Channel Dredge Structure Not Applicable – No structure

Notes. FMD = future maintenance dredging PM = project mile ROD = record of decision SMA = sediment management area

The technologies assigned by the ROD are compatible with the site factors and physical conditions at PM 10.92 and will be carried forward and evaluated further in RD. Figure 6-1 shows the applicable dredging concept for this cross section. No further evaluation is necessary in this BODR.

6.1.2 RIS&G Barge Berth (PM 11.14) The ROD technology assignments in the vicinity of PM 11.14 are shown in Figure 5-2b and summarized in Exhibit 6-2.

Exhibit 6-2. ROD Technology Assignment by River Region, PM 11.14 Riverbank Not Applicable – Wall, no Riverbank Shallow Not Applicable – Wall, no Shallow Intermediate Dredge FMD Dredge Nav. Channel Dredge Structure Not Applicable – No SMA behind/under structure

Notes. FMD = future maintenance dredging PM = project mile ROD = record of decision SMA = sediment management area

Dredging, which is called for under the ROD, is the apparent compatible technology at PM 11.14 and will be carried forward and evaluated further during RD.


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Dredging Concept (PM 11.14) A dredging concept at RIS&G is presented in Figure 6-2 and includes the following specific considerations:

Operations/Access

o Coordination of RIS&G upland and barge offload operations would be required during remediation activities.

o Implementing the RA would require partial or full shutdown of the offload operations. The peak season at RIS&G is May to October, which would require operations to be temporarily suspended or relocated to another facility; alternatively, remediation could shift to the non-peak, winter season.

o Access for conducting the remediation would be primarily from the water.

Dredging Concept

o Dredging does not impede future vessel clearance and/or maintenance dredging.

o Dredging at the face of structures (i.e., the existing retaining wall) may affect stability and require shoring.

6.1.3 ODOT Outfall WR-306 (PM 11.15) The ROD technology assignments in the vicinity of PM 11.15 are shown in Figure 5-2c and summarized in Exhibit 6-3.

Exhibit 6-3. ROD Technology Assignment by River Region, PM 11.15 Riverbank1 If erosive: Excavate and/or Cap, or Fill and Cap Shallow Dredge Intermediate Dredge FMD Dredge Nav. Channel Dredge Structure Not Applicable – No SMA behind/under structure

Notes. 1No Riverbank SMA. Adjacent to SMA and included should remediation be needed for erosive conditions or remedy protection. FMD = future maintenance dredging PM = project mile ROD = record of decision SMA = sediment management area

Dredging, which is called for under the ROD, is the apparent compatible technology at PM 11.15 and will be carried forward and evaluated further during RD.

Dredging Concept (PM 11.15) Figure 6-3 shows the applicable dredging concept for this cross section. Dredging near the outfall could require re-construction of the outfall and failing steep bank, potentially requiring access for the work from the adjacent Glacier NW upland and from in-water.

Operations/Access

o Coordination of RIS&G upland and barge offload operations would be required during remediation activities.


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o Implementing the RA would require partial or full shutdown of the offload operations. The peak season at RIS&G is May to October, which would require operations to be temporarily suspended or relocated to another facility; alternatively, remediation could shift to the non-peak, winter season.

o Access for conducting the remediation would be primarily from the water.

Dredging Concept

o Oversteepened riverbank slopes would require stabilization and/or bank layback to remove material before dredging to mitigate potential bank failure into the dredge area.

o Dredging does not impede future vessel clearance and/or maintenance dredging.

o Dredging adjacent to structures (i.e., the existing adjacent RIS&G block retaining wall return that runs west to east) may affect stability and require shoring.

o Dredging near the outfall could require re-construction of the outfall and failing steep bank, potentially requiring access for the work from the adjacent Glacier NW upland and from in-water.

6.1.4 Glacier NW Barge Dock (PM 11.19) The ROD technology assignments in the vicinity of PM 11.19 are shown in Figure 5-2d and summarized in Exhibit 6-4.

Exhibit 6-4. ROD Technology Assignment by River Region, PM 11.19 Riverbank1 If erosive: Excavate and/or Cap, or Fill and Cap Shallow Dredge (see Structure, below) Intermediate Dredge (see Structure, below) FMD Dredge Nav. Channel Dredge Structure Cap


Figure 6-4a shows a concept of a toe wall for capping under the barge dock with dredging in front of the barge dock. This concept is not practical because it would require installation of an ~20+ ft-high cantilever toe wall to allow for construction of a cap at a 2H:1V backslope. Dredging is the apparent compatible technology at PM 11.19 and will be considered further during RD.

Dredging Concept (PM 11.19) Figure 6-4b shows a dredging concept at and adjacent to the barge dock. It includes the bank layback of the wedge of material at the top of the slope and dredging of the material beneath and in front of the dock based on the following considerations:

Operations/Access


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o Remediation could be performed during the in-water work window (July through October) in the area north of Glacier NW barge dock.

o Glacier NW main dock operations peak during the in-water work window requiring consideration of an expanded work window to complete active remediation.

o Implementing RA would require partial or full shutdown of operations at the barge dock.

o Upland access to the riverbank is possible at Glacier NW north of the barge dock. Given the operational activities, access from the upland area is much more limited south of the Glacier NW barge dock.

o Bank layback may be constrained by current upland operations.

o Glacier NW has a permitted, certified City of Portland Greenway, to be re-established following remediation. There is no new “future human access” component to Glacier’s currently certified City of Portland Greenway. Glacier’s Greenway was established consistent with the Willamette Greenway plan for River Industrial zones which is intended to promote river-dependent industries while preserving and enhancing the riparian habitat. While there is provision in the guidance for considering public access where practical, this is a private, secure facility with no current or planned future public access. The Greenway will be addressed as part of the Alternatives Evaluation, 30% and 60% Design.

Dredging

o Oversteepened riverbank slopes would require stabilization and/or bank layback to remove material adjacent to the barge dock (not under the barge dock) before dredging to mitigate potential bank failure into the dredge area.

o Dredging would be implemented around the barge dock and could potentially employ the use of a long-reach excavator to dredge as needed/able beneath the dock.

o Remedy may require limited diver dredging to remove sediments under the dock.

o Riprap armoring would be placed as needed to protect against erosion.

6.1.5 Glacier NW Open Slope (PM 11.24) The ROD technology assignments in the vicinity of PM 11.24 are shown in Figure 5-2e and summarized in Exhibit 6-5.

Exhibit 6-5. ROD Technology Assignment by River Region, PM 11.24 Riverbank1 If erosive: Excavate and/or Cap, or Fill and Cap Shallow Dredge Intermediate Dredge FMD Dredge Nav. Channel Dredge Structure Not Applicable – No structure

Notes.


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1No Riverbank SMA. Adjacent to SMA and included should remediation be needed for erosive conditions or remedy protection. FMD = future maintenance dredging PM = project mile ROD = record of decision SMA = sediment management area

Dredging is the apparent compatible technology at PM 11.24 and will be considered further during RD.

Dredging Concept (PM 11.24) Figure 6-5 shows a dredging concept at the Glacier NW open slope. It includes a bank layback of the wedge of material at the top of the slope, a retaining wall at the top of the slope to limit encroachment into the adjacent upland, and dredging of the material on the face of the slope. The dredging concept includes the following considerations:

Operations/Access

o Implementing RA would require partial or full shutdown of operations at the barge dock.

o Upland access is limited south of the Glacier NW barge dock.


o Glacier NW has a permitted, certified City of Portland Greenway, to be re-established following remediation.

Dredging

o Oversteepened riverbank slopes would require stabilization and/or bank layback to remove material before dredging to mitigate potential bank failure into the dredge area.

o Retaining walls may be required to limit encroachment of a dredge cut into adjacent upland.


o Dredging in the open slope area.

6.1.6 Glacier NW Main Dock (PM 11.31) The ROD technology assignments in the vicinity of PM 11.31 are shown in Figure 5-2f and summarized in Exhibit 6-6.


Notes. 1No Riverbank SMA. Adjacent to SMA and included should remediation be needed for erosive conditions or remedy protection. FMD = future maintenance dredging PM = project mile


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ROD = record of decision SMA = sediment management area

Figure 6-6a shows a conceptual configuration of a toe wall for conventional capping on the slope under and behind the dock, with dredging in front of the dock. This concept is not practical because it would require the installation of a ~20+ ft-high cantilever wall. The toe wall would be required to retain the cap at a 2H:1V backslope, while also maintaining a depth of -38 ft NAVD88 (-43 ft CRD) in the FMD Region at the dock face.

Given that, both dredging and hybrid capping appear to be compatible technologies at PM 11.31 and will be considered further during RD.

Glacier NW has indicated that removal and subsequent replacement of a portion of its main dock, while not currently anticipated, could be evaluated if needed to reasonably implement remediation at and behind the dock. This approach will be included in the alternatives evaluation (see Sections 8 and 9).

Dredging Concept (PM 11.31) Figure 6-6b shows a dredging concept beneath and behind the Glacier NW main dock. It includes bank layback of the wedge of material at the top of the slope, and dredging of the material in the FMD Region and beyond, as well as beneath and behind the face of the dock to the extent practical. The dredging concept includes the following considerations:

Operations/Access

o Shift remediation to coincide with operational, off-peak winter season in the area of the Glacier NW main dock.

o Glacier NW main dock operations peak during the normal in-water work window (July through October) requiring consideration of an expanded work window to complete active remediation.

o Implementing RA would require partial or full shutdown of the cement offload operations at the main dock.

o Upland access is limited along the Glacier NW main dock because of upland operations.

o Bank layback is constrained by current upland operations.


Dredging

o Oversteepened riverbank slopes in this reach were flattened and riprapped during construction of the main dock. Retaining walls may be required to limit encroachment into upland from dredging. Portions of SMA slopes remain oversteepened.

o Dredging would be performed in the open slope area and around the dock structure and could potentially employ the use of a long-reach excavator or other limited access equipment to dredge as needed/able beneath the dock. The


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Selected Remedy may require diver dredging as a supplemental cleanup operation.



ACB Mat Cap/Dredging Concept (PM 11.31) Figure 6-6c shows an alternate hybrid capping concept composed of ACB mats. This concept is based on the same Operations/Access and Alternative Access considerations described in the above dredging concept, as well as the following additional considerations:

ACB Mat Cap/Dredging

o In place of a conventional engineered cap, cover the sediment on the oversteepened SMA slope with concrete blocks tied together with steel cables anchored to pilings at the top of the slope (ACB mat). Incorporate non-woven geotextile fabric beneath the ACB mat for sediment retention, and possibly activated carbon quilted into the geotextile or use a geotextile, such as reactive core mat (RCM), as needed to manage potentially dissolved COCs in porewater.

o Dredging would be performed beyond the toe of the slope in the FMD and Navigation Channel Regions

6.1.7 PacifiCorp Submarine Cable Crossing (PM 11.36) The ROD technology assignments in the vicinity of PM 11.36 are shown in Figure 5-2g and summarized in Exhibit 6-7.

Exhibit 6-7. ROD Technology Assignment by River Region, PM 11.36 Riverbank1 If erosive: Excavate and/or Cap, or Fill and Cap Shallow Dredge Intermediate Dredge FMD Dredge Nav. Channel Dredge Structure Not Applicable – No structure


Active remediation at and near the submarine electrical cable crossing would be possible only if the cable crossing were first removed from service. Assuming that cable relocation is determined to be feasible, capping and dredging would then appear to be compatible technologies at PM 11.36 to consider further during RD.

Dredging Concept (PM 11.36) Figure 6-7a illustrates a dredging concept and includes the following considerations:

Operations/Access


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o Relocation of the submarine electrical cable crossing will be required before active remediation can be completed in the existing cable crossing alignment.

o Access to the area between the Glacier NW main dock and Cargill main dock is limited by the presence of ships at the docks during the peak operation of both facilities requiring consideration of an expanded in-water work window to complete active remediation.

o Shift remediation to the non-peak season in the area between Glacier NW main dock and Cargill main dock.


Dredging

o Remove de-energized cables as necessary to facilitate RA construction.

o Oversteepened upper slopes would require stabilization or bank layback to remove material before dredging to mitigate potential bank failure into the dredge area.

o Dredging in the open slope area.

o Riprap armoring would be placed over excavated substrate in the wave zones.

Capping and Dredging Concept (PM 11.36) Figure 6-7b shows a combination of dredging of the flatter slope below an elevation of roughly -20 ft NAVD88 and capping the upper portion of the slope above -20 ft NAVD88 to limit encroachment of dredging into the adjacent upland. This concept includes the following considerations:

Engineered Cap/Dredging Concept

o Remove de-energized cables as necessary to facilitate RA construction.

o Dredge in flatter slope area, roughly below elevation -20 ft NAVD88.

o Construct a toe buttress to retain capping material above ~-20 ft NAVD88.

o Construct cap above ~-20 ft NAVD88 with riprap armoring in the wave zone, and with dredging as necessary to accommodate the thickness of the engineered cap.

6.1.8 Cargill Former Crane Tramway, Outfall OF43 (PM 11.39) The ROD technology assignments in the vicinity of PM 11.39 are shown in Figure 5-2h and summarized in Exhibit 6-8.

Exhibit 6-8. ROD Technology Assignment by River Region, PM 11.39 Riverbank1 If erosive: Excavate and/or Cap, or Fill and Cap Shallow Dredge Intermediate Dredge FMD Dredge Nav. Channel Dredge Structure Evaluate removal of former crane tramway, collocated

with functional OF43. Dredge or cap.


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Notes. 1No Riverbank SMA. Adjacent to SMA and included should remediation be needed for erosive conditions or remedy protection. FMD = future maintenance dredging OF = outfall PM = project mile ROD = record of decision SMA = sediment management area

Figure 6-8a shows a concept of a toe wall for capping under the former crane tramway with dredging in front of the structure. Conventional capping is not practical at PM 11.39 under the tramway structure because it would require the installation of an ~30-ft-high cantilever wall at the toe of the slope to maintain navigation depths for the Cargill main dock and allow for construction of a cap at a 2H:1V backslope.

Diver dredging around remnant pilings is an apparently compatible technology at PM 11.39, although it may not be operationally or economically practical given the slow production rates. Hybrid capping or covering with or without dredging, and dredging with bank layback are also apparent compatible technologies at PM 11.39. All three will be further considered during RD. The thin Target Material in this area will be investigated during RD to confirm its presence, especially on the oversteepened areas.

Diver Dredging Concept (PM 11.39) Figure 6-8b illustrates a diver dredging concept at PM 11.39 based on the following considerations:

Operations/Access

o Access to the area between the Glacier NW main dock and Cargill main dock is limited by the presence of ships at the docks during the peak operation of both facilities requiring consideration of an expanded in-water work window to complete active remediation.

o Shift remediation to non-peak winter season in the area between the Glacier NW main dock and Cargill main dock.

o Remnant pilings exist throughout much of the area, likely from the Irving Dock dating back to the late 1800s. Pulling the pilings is not advised because they are contributing to the stability of the oversteepened slopes. Pilings can be cut off at the mudline as part of remediation.

o A former crane tramway structure extending from the shoreline is no longer in service at the site and may be removed as needed to facilitate remediation.

o The City’s OF43 would be stabilized or replaced as needed to facilitate remediation. Replacement of the outfall would likely follow the removal of the former crane tramway structure. The potential replacement of OF43 will be evaluated as part of the Alternatives Evaluation and 30% Design, including any erosive potential. .


Diver Dredging Concept


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o Conventional dredging is not viable due to the presence of the remnant pilings. Diver-operated dredging, with or without first mechanically dredging, would be required to remove sediment.

o Diver-dredging is slow, about 15 cubic yards per diver crew per day. Clearing each 100 ft of shoreline through the piling field could take 30 to 50 diver days to complete. There are approximately 800 linear ft of pilings, which would take approximately 240 to 400 diver days to complete, making diver dredging of the full area operationally and economically not practical.

o Diver dredging will be further evaluated as a limited application technology during 30% Design, including compiling additional diver-dredge production data when available and applicable.

Hybrid Cap/Dredging Concept (PM 11.39) Figures 6-8c and 6-8d show two alternate hybrid capping concepts at PM 11.39, one using ACB mats and one incorporating the remnant pilings. They include the same considerations for Operations/Access described in the diver dredging concept, as well as the following additional design considerations:


o In place of a conventional engineered cap, cover the sediment on the oversteepened slope with an ACB mat consisting of concrete blocks tied together with steel cables anchored to pilings at the top of the slope.

o Incorporate non-woven geotextile fabric beneath the ACB mat for sediment retention, or possibly underlay the ACB mat with RCM as needed to manage potentially dissolved COCs in porewater.

o Dredging would be performed beyond the toe of the slope in the FMD and Navigation Channel Regions.

Remnant Piling Cap/Dredging

o Span the distance between adjacent pilings at roughly the same elevation with 1- to 3-ft-high structural members to create a series of parallel walls on the slope. Place granular backfill between the walls to construct a cap on the oversteepened slope.

o Incorporate activated carbon into the fill as needed to manage potentially dissolved COCs in porewater.


Bank Layback and Dredging Concept (PM 11.39) Figure 6-8e shows a bank layback concept at PM 11.39. This concept includes the same considerations for Operations/Access described in the diver dredging concept, as well as the following additional considerations:

Bank Layback and Dredging


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o Oversteepened slopes would be laid back to mitigate the potential for bank failure from pulling out the remnant pilings.

o Retaining walls may be required to limit encroachment into upland from dredging and bank stabilization or layback.

o Remove remnant crane tramway and pull remnant pilings.

o Conventional dredging upon the removal of the remnant pilings.

6.1.9 Cargill Main Dock (PM 11.46) The ROD technology assignments in the vicinity of PM 11.46 are shown in Figure 5-2i and summarized in Exhibit 6-9. 38



Figure 6-9a shows a concept of a toe wall for conventional capping under and behind the Cargill main dock that is not practical at PM 11.46 because it would require the installation of an ~20-ft-high cantilever wall at the toe of the slope to maintain navigation depths at the Cargill main dock and allow for construction of a cap at a 2H:1V backslope.

Diver dredging around remnant pilings appears to be a compatible technology at PM 11.46, although it may not be operationally or economically practical due to slow production rates. Hybrid capping with or without dredging, and dredging with bank layback may be compatible technologies at PM 11.46 provided it is compatible with the existing soldier pile and tie back retaining walls. All three will be further considered during RD. The thin Target Material in this area will also be investigated during RD to confirm its presence, especially on the oversteepened slope areas beneath dock structures.

Cargill has indicated that removal and subsequent replacement of its main dock, while not currently anticipated, could be evaluated if needed to reasonably implement remediation at and behind the dock. This approach will be included in the alternatives evaluation (see Sections 8 and 9).

Diver Dredging Concept (PM 11.46)

38 The cross section at PM 11.46 represents general conditions along the mid-length of the Cargill main dock. PM 11.46 was not found to contain Target Material, as shown in Figure 5-1k, and does not pass through the presumptive PCB SMA (see Figure 2-23), while adjacent areas along the Cargill main dock (PM 11.44 and 11.48) are within the presumptive PCB SMA; therefore, Target Material in this area is shown for concept development only. The actual extent of the SMA at the Cargill dock will be refined during RD.


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Figure 6-9b illustrates a diver dredging concept at PM 11.46. The concept includes the following considerations:

Operations/Access

o Cargill main dock operations peak during the normal in-water window (July through October) requiring consideration of expanded work windows to complete active remediation.

o Shift remediation to non-peak season in the area at Cargill main dock, unless other arrangements for access are established allowing for the temporary discontinuation of operations during the normal in-water window, to be evaluated during RD.

o Remnant pilings exist throughout the area, most of them likely from the Irving Dock dating back to the late 1800s. Pulling out the pilings is not advised because they are contributing to the stability of the oversteepened slopes. Pilings can be cut off at the mudline as part of remediation.


Diver Dredging Concept

o Oversteepened riverbank slopes would require stabilization or bank layback before dredging to mitigate potential for bank failure into the dredge area. Bank layback may be complicated in this area by limited space between the top of the bank and upland structures including buildings, roads, and shoreline stability features.

o Conventional dredging is not viable given the presence of the remnant pilings and the active dock structure. Diver-operated dredges would be required to remove sediment.

o Diver-dredging is slow, about 15 cubic yards per diver crew per day. Clearing each 100 ft of shoreline through the piling field could take 30 to 50 diver days to complete. There are approximately 800 linear ft of pilings, which would take approximately 240 to 400 diver days to complete, making diver dredging of the full area operationally and economically not practical. However, diver dredging will be evaluated during the Alternatives Evaluation on a limited or conditional application basis, including dredging under docks.

Hybrid Cap/In Situ Treatment/Dredging Concepts (PM 11.46) Figures 6-9c, 6-9d, and 6-9e show three alternative hybrid capping concepts for behind and under the dock at PM 11.46: using ACB mats, incorporating the remnant pilings, and in situ technology applying AquaGate® (i.e., PAC) or similar product. They include the same Operations/Access considerations described in the diver dredging concept, as well as the following additional considerations:


o Cut remnant pilings at mudline.


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o In place of a conventional engineered cap, cover the sediment on the oversteepened slope with the ACB mat.

o Incorporate non-woven geotextile fabric beneath the ACB mat for sediment retention, or possibly underlay the ACB mat with RCM as needed to manage potentially dissolved COCs in porewater.


Remnant Piling Cap/Dredging

o Cut remnant pilings at 1 to 3 ft above mudline.

o Span the distance between adjacent pilings at the same elevation with 1- to 3-ft-high structural members to create a series of parallel walls on the slope. Place granular material between the walls to construct a cap on the oversteepened slope.

o Incorporate activated carbon into the fill as needed to manage potentially dissolved COCs in porewater.


AquaGate®/ Dredging

o Place a layer of AquaGate® (or similar product) on the slope to reduce the bioavailability of organic compounds. This in-situ technology may be most viable in areas where the Target Material is relatively thin as appears to be the case along much of the slope behind the Cargill main dock.


Bank Layback and Dredging Concept (PM 11.46) Figure 6-9f shows a bank layback concept behind the dock at PM 11.46 and includes the same Operations/Access considerations as described in the diver dredging concept, as well as the following additional considerations:

Full Bank Layback and Dredging

o Oversteepened riverbank slopes would be stabilized or laid back to mitigate the potential of bank failure from pulling out remnant pilings. Bank layback may be complicated in this area by limited space between the top of the bank and upland structures including buildings, roads, and shoreline stability features.

o Pull remnant pilings. This concept would require a detailed geotechnical evaluation to determine if slope stability could be maintained after pulling pilings.

o Dredging in remnant piling field upon the removal of the remnant pilings. Dredging may be constrained by limited access behind main dock.


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6.1.10 Summary of Technologies Exhibit 6-10 provides a listing of the technologies and design alternatives at each representative cross section that, unless not practical, will be taken forward to 30% Design.

Exhibit 6-10. Summary of RD Technology Alternatives

Station Figure Number Adjacent Upland Remediation Technology Concepts

PM 10.92 6-1 Sakrete Dredging PM 11.14 6-2 RIS&G Dredging, Shoring

PM 11.15 6-3 ODOT Outfall WR-

306 Dredging, Bank layback/stabilization

PM 11.19 6-4a Glacier NW Barge

Dock Toe Wall / Capping - not practical

6-4b Dredging, Bank layback / stabilization

PM 11.24 6-5 Glacier NW Open

Slope Dredging, Bank layback / stabilization

PM 11.31 6-6a

Glacier NW Main Dock

Toe Wall / Capping - not practical 6-6b Dredging, Bank layback / stabilization 6-6c ACB Mat Capping and Dredging

PM 11.36 6-7a Open slope at

PacifiCorp Cable Crossing

Dredging, Bank layback / stabilization

6-7b Engineered Cap & Dredging

PM 11.39

6-8a

Former Tramway and OF43

Toe Wall / Capping - not practical 6-8b Diver Dredging / Dredging 6-8c ACB Mat Capping and Dredging 6-8d Remnant Piling Cap / Dredging 6-8e Bank Layback and Dredging

PM 11.46

6-9a

Cargill Main Dock

Toe Wall / Capping - not practical 6-9b Diver Dredging / Dredging 6-9c ACB Mat Capping and Dredging 6-9d Remnant Piling Cap / Dredging 6-9e AquaGate© / Dredging 6-9f Full Bank Layback / Dredging

Notes. ACB = articulated concrete block ODOT= Oregon Department of Transportation OF = outfall PM = project mile RD = remedial design RIS&G = Ross Island Sand & Gravel Diver dredging will be evaluated during the Alternatives Evaluation on a limited or conditional application basis, including dredging under docks.

6.2 Step 5: Effectiveness The technologies identified through Steps 1 through 4 (see Section 5 and section 6.1) as being compatible with facility and physical site conditions are evaluated below to assess their effectiveness using the following environmental performance factors:

Porewater management

Erosion control


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Zero flood rise and navigation

Limiting environmental exposure during dredging

In-water work windows/habitat

Water quality controls

Materials disposal

Source material

Green remediation

6.2.1 Porewater Management Management of porewater is discussed in Section 2.8.2 with evaluation of groundwater advection through contaminated sediment using CapSim demonstrating that PCBs and other HOCs can be reliably contained using a simple sand cover as a chemical isolation layer. Based on these findings, the remediation concepts presented in this BODR do not specifically recommend the use of reactive amendments for conventional capping. These findings will be confirmed during RD. Refinement of cap composition will be performed for each specific location identified in RD for capping, including any proposed hybrid capping.

6.2.2 Erosion Control Figure 2-15 shows that most of the RM11E Project Area is susceptible to high-impact erosive forces, including those caused by river hydrodynamics, propeller wash (including docking of ships and movements in the turning basin), and shoreline wave action. The capping technologies identified in this BODR include an armoring layer to protect against erosion as well as armoring in the wave zone to protect against ongoing loss of the shoreline. Upon selection of areas to be capped during RD, site- and condition-specific armoring will be designed to protect capped areas from potential erosive forces (e.g., propeller wash, waves, river currents, and outfall discharges). Analyses will include more frequent floods with higher peak flows to account for future climate change (see Section 2.4.5).

6.2.3 Zero Flood Rise and Navigation Two waterway considerations for the RM11E RA are zero flood rise and navigation. Both issues have implications on potential remedial options, as discussed below.

Zero flood rise refers to FEMA regulations prohibiting encroachments in the waterway that would result in any increase in flood levels during base flood discharge (44 CFR 60.3(d)(3) - Floodplain management for flood-prone areas).

The Navigation Channel on the Lower Willamette River is present in the RM11E Project Area. The channel has been federally authorized to be deepened by 3 ft from its current maintained depth.

Zero Flood Rise FEMA regulations require that projects in a floodway be reviewed to determine if the project will increase flood heights. Two evaluations of potential flood rise from the PHSS


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RA are summarized below, one dated March 2012 from the draft FS (Anchor QEA et al., 2012), and another dated June 2016 included in EPA’s final RI/FS (EPA, 2016b).

A PHSS-wide HEC-RAS no-net rise analysis was completed as part of the PHSS draft FS (Appendix Lb in Anchor QEA et al., 2012) for multiple PHSS-wide remedial alternatives that were under consideration at the time. The analysis was completed for both 100- and 500-year flood events. The report concluded:

Footprint of Remediation

o PHSS remedial alternatives included in the PHSS draft FS with larger footprints throughout PHSS (such as Alternative F) generally had higher levels of model-predicted increases in water surface elevation (WSE) (0.069 ft for Alternative F-i) than alternatives with smaller footprints, such as Alternative B (0.011 ft for Alternative B-i).

o For smaller RA footprints, the predicted increase of WSE was greater for removal alternatives as compared to integrated alternatives (with both removal and capping).

100-Year vs. 500-Year Flood Events

o The predicted maximum increase of WSE was less for the 500-year flood event than for the estimated 100-year flood event.

No Measurable Flood Rise

o The report concluded that all the maximum increases in predicted WSE from the modeling efforts for site-wide remediation were effectively immeasurable by the precision of the model.

EPA’s PHSS RI/FS included Appendix P, Flood Rise Evaluation Feasibility Study (EPA, 2016b). Balancing cut and fill throughout the PHSS was considered as a means to minimize the potential for unacceptable flood rise. For the purposes of the FS, an evaluation of compliance with no increase in flood heights for each alternative was performed by documenting and comparing estimated volumes of remedial technologies, such as capping and dredging, to determine if the balance cut/fill objective is achievable.

The EPA report concluded:

For each alternative the total volume of fill is less than the total volume removed, resulting in a net cut volume. While this is not entirely balanced with respect to cut/fill, it does indicate that there is no net increase in channel depth, minimizing potential increase to flood rise levels due to technology assignments, and fulfilling the requirements for protection of human health and the environment and compliance with ARARs with respect to flood rise.

Given the findings of both Appendix Lb of the draft FS, and EPA’s Appendix P of the FS, the ROD-prescribed remedy, including ROD-identified technologies at RM11E, are expected to comply with zero flood rise requirements. Zero flood rise will be addressed during RD.


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Navigation The Lower Willamette River Navigation Channel is currently maintained at a depth of -35 ft NAVD88, with the potential for deepening to its authorized depth of -38 ft NAVD88. USACE has deferred deepening to the authorized depth pending resolution of legal and technical issues associated with PHSS. Cargill and Glacier NW expect to eventually deepen the ship berths in front of their facilities to match the Navigation Channel when the channel is deepened and maintained to the authorized depth of -38 ft NAVD88 (-43 ft CRD). Within the RM11E Project Area, the Navigation Channel is generally at or below this authorized depth except near the west edge of the channel and an area between the Cargill and Glacier NW main docks (see Figure 5-1i, PM 11.36). Dredging is the RM11E preferred active remediation technology in the Navigation Channel and adjacent FMD Regions. Dredging these areas as part of RD to remove Target Material will not conflict with future deepening and associated adjustment of side slopes of the channel. Identified remedial technologies will be further refined and developed in RD to designate where Target Material is confined or removed at the interface between the FMD Region and adjacent slopes and docks.

6.2.4 Limiting Environmental Exposure During Dredging To strengthen consideration of an expanded in-water work window, enhanced environmental dredging methods, such as described below, are proposed to be implemented to reduce environmental exposure from dredging at RM11E. The purpose of environmental dredging is to remove contaminated sediment and reduce exposure to COCs. Depending on how the dredging is completed, there can also be temporary adverse environmental exposures from dredging of impacted sediment, including suspension of impacted sediment into the water column (“resuspension”), movement of dissolved COCs into the water column (“release”), and post-dredge surface layers of contaminated sediment in the dredging footprint and immediately surrounding area (“dredging residuals”) (Bridges et al., 2008).

Residuals are subdivided into two categories: “generated residuals” are post-dredging contaminated surface sediments that were dislodged during dredging and redeposited on the bed; “undisturbed residuals” are contaminated sediments that were missed by the dredging program, also referred to as undredged inventory. Based on data from projects with conventional dredging practices, the average concentration of COCs in generated residuals can reasonably be estimated as the average concentration of the COCs in the dredge cut. One method to manage generated residuals is to place a sand layer over the post-dredge surface following dredging, an approach that is included in the ROD (see Section 14.2.2 of the ROD).

The U.S. Department of the Army Engineering Research and Development Center concluded in 2013 that dredging procedures have evolved to lessen resuspension, release, and residuals (Gustavson and Schroeder, 2013) and makes specific reference to a paper titled Urban River Remediation Dredging Methods that Reduce Resuspension, Release, Residuals and Risk (Fuglevand and Webb, 2012). That paper presents the following RDMs that, when implemented together, reduce the potential exposures from environmental dredging:


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RDM-1. DoC Elevation. Pre-define the elevation of the depth of contamination (DoC) using high-quality sediment core data integrated into a digital terrain model (DTM) of the site. This will involve specific sediment sampling methods and sample spacing to define the extent of RT-impacted sediment with good certainty.

RDM-2. Design Dredge Elevation and Dredge Prism. Set the design dredge elevation below the DoC DTM to account for the vertical accuracy of the selected dredge equipment (usually 4 to 6 inches).

RDM-3. Once and Done. Provided the sediment sampling has been sufficient to define the extent of RT-impacted sediment with good certainty, perform planned dredging according to the dredge prism without post-dredge sediment confirmation sampling for chemical monitoring and associated re-dredging. The removal can be confirmed by hydrographic surveys that verify removal of the target material to the design dredge elevation.

RDM-4. Sand Cover. Place a sand cover over dredge cuts in each subunit of the site as soon as practical after subunit dredging is complete. Depending on site constraints, the placement of the sand cover could occur within 1 or 2 weeks of dredging.

RDM-5. Dredging Equipment. Select the appropriate dredging equipment based on the site conditions and accuracy requirements, with an articulated fixed-arm dredge identified for small to medium-sized urban river projects within the depth limits of available excavators.

RDM-6. Dredging Bucket. Use an enclosed double-arc cutting bucket to limit loss of sediment to the water column by limiting the plowing/remolding of the sediment during capture.

RDM-7. Dredge Bucket Positioning. Use high accuracy global positioning systems (GPS; such as dual-frequency receivers with virtual reference system [VRS] correction, or RTK systems) integrated into electronic dredge positioning systems/software (such as Dredge Pak, WinOps, or Clam Vision) for accurate bucket positioning. The instrumentation can include multiple GPS antennae on the excavator to account for movement of equipment, along with inclinometers on the excavator arm and stick to establish position of the bucket.

RDM-8. Stair-Step Dredge Cuts on Slopes. Implement stair-step dredge cuts on steeper slopes to reduce sloughing of sediment. The sizing and spacing of the steps normally are established during RD based on the inclination of the slope, the thickness of Target Material, and the contractor’s equipment.

RDM-9. Dredge Slopes with Articulated Fixed-Arm Dredge. Use an articulated fixed-arm dredge for improved bucket control and reduced sediment disturbance on steeper slopes.

RDM-10. Water Management. Remove water from sediment barges actively during dredging (no direct overflow) for processing and management as dredging return water.


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RDM-11. Active Oversight and Monitoring. Perform continuous competent technical monitoring of the dredging process with an integrated adaptive management program to adjust and modify the RDMs as needed to accommodate the site conditions.

Consistent with the ROD’s “residual management layer” (ROD 14.2.9.2), the RDMs included placement of a sand cover (RDM-4) to limit exposure of residuals following dredging.

These RDMs were applied in 2013 to 2015 in the Duwamish Waterway in Seattle, Washington, for Boeing’s Plant 2 sediment remediation project, where PCBs were the primary COC. While EPA initially required Boeing to install a sheet pile wall or coffer dam around the dredging area to control releases during dredging, a subsequent review of the RDM approach by both EPA and USACE led to EPA’s acceptance of the RDMs without a requirement of a containment wall or silt curtains. Engineering controls will be considered during Alternatives Evaluation and 30% Design and refined as part of 60% Design based on site-specific factors including consideration of an expanded in-water work window.

Water quality monitoring of turbidity and PCBs during the 3-year dredging project confirmed the effectiveness of the RDMs in an urban waterway, as follows (Amec Foster Wheeler et al., 2016):

Release. Measured chemical exceedance of the PCB chronic water criterion (0.03 ug/L) occurred on only two occasions during the 3 years of construction, demonstrating the RDM effectiveness in controlling resuspension and release. One exceedance occurred during the second construction season at 0.067 ug/L while debris was being removed along the shoreline, and the other occurred during the third construction season at 0.031 ug/L also during nearshore debris removal.

Resuspension. During 149 days of water quality monitoring, there were 14 days of dredging with measured exceedances of the turbidity criterion (5 nephelometric turbidity units [NTUs] over background) ranging from 5.2 to 18.9 NTUs over background and averaging 10 NTUs over background, demonstrating the effectiveness of the RDMs in controlling resuspension. As a point of comparison, during placement of clean, double-washed granular backfill, there were 15 days with measured exceedances of the same turbidity criterion ranging from 9.8 to 90.2 NTUs over background and averaging 28 NTUs over background.

Generated Residuals. Surface sediment samples were collected following dredging and before placing sand backfill. The average total PCB concentration of the post- dredging surface was 19 ug/kg dw. In comparison, the pre-dredge concentrations of the in situ sediment averaged about 1,050 ug/kg dw total PCBs with concentrations as high as 110,000 ug/kg dw, demonstrating the effectiveness of the RDMs at limiting post-dredge residuals.

Undisturbed Residuals. Subsurface sediment samples were collected following dredging to identify undredged inventory. PCBs were measured at 1 to 2 ft below the post-dredge surface at 17 coring stations. At 15 of those stations, the PCBs at 1 to 2 ft depth were undetected (<5 ug/kg dw), and at two stations the measured PCBs were less than 15 ug/kg, dw, demonstrating the effectiveness of the RDM pre-


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dredge coring program in mapping the DoC and supporting the once and done approach.

6.2.5 In-Water Work Windows/Habitat ODFW has issued general in-water work timing guidelines to limit potential adverse impacts to fish from marine construction activities. These timing guidelines establish periods during which in-water work can occur (July 1 through October 31 for all in-water work river-wide, and December 1 through January 31 for deep water navigation dredging) to minimize the exposure of juvenile salmonids to construction activities.

Several facilities operating within the RM11E Project Area (e.g., Cargill, Glacier NW, and RIS&G) are at peak operations during the typical work window (July 1 through October 31) recommended by the guidelines. The RM11E Group is proposing to conduct remediation activities within an expanded in-water work window from July 1 through February 28 within all depth zones for this entire period. An expanded in-water work window would expedite remediation, reduce the duration that fish remain exposed to the effects of contaminated bed sediment, reduce the impacts of remediation on local business and the regional businesses dependent on them, and, as detailed in Appendix C, still be protective of fish. The purpose of this section is to provide a preliminary analysis of the effects on fish if the remediation work window were expanded.

Work at RM11E would maximize active remediation during the July to October period to the extent practical while maintaining the ability of the terminals to operate efficiently to meet seasonal demands.

The RM11E Group also proposes to use refined RDMs that have been developed since the work windows were originally developed. The RDMs have been used in similar remediation work and have been demonstrated to be effective in limiting the release of suspended sediment and contaminants (Section 6.2.4). These RDMs were successfully implemented by the RM11E design team on a similar remediation project (Boeing Plant 2 in the Lower Duwamish Waterway, Washington). Using these methods, the Boeing Plant 2 remediation met stringent water quality standards for suspended sediment and PCBs during the course of a 3-year project. Implementing these methods in the RM11E Project Area would reduce the extent of juvenile fish exposure to potential impact mechanisms and limit their potential exposure to a relatively small area.

Appendix C provides a preliminary analysis of the potential effects on juvenile Chinook salmon resulting from the conduct of remediation activities at the RM11E Project Area within an expanded work window. Juvenile Chinook were selected for the preliminary analysis as an appropriate representative species because its varied life history poses the greatest potential for overlap with the proposed expanded work windows. Appendix C includes an assessment of fish presence during an expanded in-water work window, as well as an evaluation of the potential exposures of fish to COCs and turbidity.

Appendix C concludes that an expanded in-water work window would be subject to higher use by juvenile Chinook salmon than the typical in-water work window. However, given the proposed use of contemporary dredging methods, the potential for exposure of juvenile Chinook to PCBs or injurious levels of turbidity during the expanded in-water work window would be low. Further, based on the size and residence time of the fish that would


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be present, any use of the site during this time will likely be of a brief enough duration to preclude injury from these means.

Other topics related to ecological habitat will be addressed during RD after site-specific remediation plans are identified. Those topics include potential habitat modifications associated with various remedial technologies, including the potential loss of shallow water habitat, with respect to the substantive requirements of Section 404(b)(1) of the CWA, Essential Fish Habitat (EFH) requirements of the Magnuson-Stevens Fishery Conservation and Management Act, ESA, and the City’s Willamette Greenway Plan. The RD will identify remedial technology approaches to limit adverse effects on threatened or endangered species and designated critical habitat; and identify potential mitigation options for unavoidable impacts if necessary.

The approach will evaluate the work window differences within the context of whole project alternatives. The issue of work windows will be addressed within the project’s ESA review within a project-specific Biological Assessment (BA). However, rather than selecting an alternative and then conducting ESA review, the potential impacts of each alternative will be described within an analysis suitable for supporting an ESA review. Therefore, each alternative or set of alternatives will have a focused BA level of analysis addressing the impacts of construction. This analysis will be presented and considered within the CERCLA evaluation of the remedial alternatives. Inclusion of this analysis within the Alternatives Evaluation will allow additional review of the significance of the trade-offs between allowing in-water work in non-typical seasons and achieving timely project completion. Following EPA’s selection of an alternative, a full RM11E BA will be submitted to support ESA review and preparation of a Biological Opinion.

6.2.6 Water Quality Controls Impacts to water quality can be affected by dredging methods and procedures associated with dredging. Traditional dredging methods, both mechanical and hydraulic, have been shown to cause resuspension and generated residuals, which can result in a release of COCs and contaminated sediment into adjacent dredged surfaces and clean areas downstream. Two main categories of controls to limit impacts to water quality are engineering controls and operational controls.

Engineering Controls Engineering controls are physical barriers installed or deployed before and during dredging operations. These include (but are not limited to): silt curtains, debris booms, oil booms, sheet pile walls, coffer dams, and other types of dams. Engineering controls are often implemented and/or required because of the assumption that they act to fully isolate an area or completely contain resuspended sediment that results from disturbance of the riverbed. However, as explained below, these controls can be ineffective, impractical, or sometimes even harmful to the overall water quality or river system:

Silt Curtains. Silt curtains are geotextile fabric curtains hung vertically on floating booms that are intended to act as barriers to contain suspended sediment in the dredging area. They are most effective in low velocity currents (< 1.0 to 2.5 ft per second) and shallow water (<10 to 15 ft) where there is little to no tidal fluctuation


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(Francingues and Palermo, 2005). Silt curtains may be applicable to the RM11E Project Area in areas of shallow water on a task-specific basis.

Sheet Pile Walls. Sheet pile walls are large, prefabricated, typically steel panels that are driven into the sediment to provide an interlocking barrier between the remedy area and the wider river system. Sheet piles are not considered implementable for the RM11E Project Area given the following drawbacks described in the Technical Guidelines for Environmental Dredging (Palermo et al., 2008):

o A sheet pile wall will be a barrier to the flow of the river. Changing the flow profile of a river by constricting cross sectional area increases the chance of flooding or erosion damage.

o A sheet pile wall system can increase the potential for scour around the outside of the contaminant area because of increased velocity of water around the structure.

o Unless installed as a hydraulic cutoff wall, such as the case for a coffer style enclosure, sheet pile systems are generally not fully enclosed systems.

o Resuspension and release of potentially contaminated sediment can occur during installation and removal of the sheet pile panels.

o A sheet pile wall constructed in the Navigation Channel would impede the Navigation Channel and would likely be prohibited.

o Sheet pile walls installed in the RM11E SMAs, including the FMD Region, would eliminate access to the active terminals by commercial vessels.

Other Engineering Controls. Other engineering controls, such as debris booms, oil booms, temporary dams, etc., may be applicable on a task-specific project basis and will be evaluated in RD where appropriate.

The development and application of engineering controls and operation controls will be through the 60% Design and the RA QAPP. It is possible that implementation of operation controls, such as the RDMs, may sufficiently manage the environmental exposure from dredging and eliminate the need for engineering controls.

Operational Controls Operational controls, such as modified dredging equipment, and controlling methodologies for removal—referred to in Section 6.1.5 as RDMs—have been shown to reduce water quality impacts during dredging (Amec Foster Wheeler et al., 2016) compared to conventional dredging practice, and may eliminate the need for engineering controls, such as silt curtains and sheet pile walls.

RDM-10 includes capture and processing of dredge water, both from the sediment barge and as released from sediment stockpiles at transload facilities. Precision environmental dredging with enclosed dredging buckets tends to produce buckets that are half full of sediment, and half full of water. Implementing environmental dredging involves handling and processing as much dredge water as dredged sediment. Multiple technologies are available to process dredge water before discharge back into the river depending on the nature of the sediment and water quality criteria. Passive methods can be effective to clarify


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dredge water associated with sandy sediment, such as (1) retaining the water in the barge while solids settle from the water column, and (2) passing dredge water through filter media, such as straw bales, to capture suspended solids. Capturing fines from dredge water associated with fine-grained sediment may require more active processing, such as adding flocculants before directing water into geotextile bags for filtration or passing dredge water through sand filters and bag filters. Depending on water quality criteria, the clarified dredge water can be passed through activated carbon filters to capture organic compounds, such as PCBs, before discharge back into the river. The selection of water processing technologies will be part of RD.

Evaluation and selection of engineering controls and operational controls for use in the RM11E Project Area will occur during RD.

6.2.7 Materials Disposal The ROD requires that dredged sediment exceeding RTs be disposed of offsite at an appropriately licensed and permitted landfill. The transportation of dredged sediment will be by truck, rail, and/or barge and will involve a sediment transload facility. Sediment transload refers to the process of transferring the dredged sediment from barges to upland storage facilities and/or to transportation modes, such as truck and rail. Transload and transport are addressed in Section 6.2.8.

Volume SMAs will be delineated by surface and subsurface contamination above RTs and where exposure is occurring or has the potential for exposure. Based on the estimated depth of impact for PCBs only (see Section 2.7.4), it is possible that 50,000 to 100,000 cubic yards of dredge material could be produced if all Target Material were removed (i.e., if no capping were implemented). Additional sediment sampling during RD, together with identification of specific areas to be dredged and capped, will provide a basis for a more specific estimate of the volume of material expected to be generated from areas where dredging is the selected remediation technology.

Waste Disposal Requirements Dredged sediment resulting from the RA will require disposal at a viable and practical disposal location, including, but not necessarily limited to, the following commercial landfills identified in the PHSS FS:

Hillsboro Landfill. Waste Management operates a RCRA Subtitle D solid waste landfill near Hillsboro, Oregon.

Wasco County Landfill. Waste Connections operates a RCRA Subtitle D solid waste landfill located near The Dalles, Oregon.

Roosevelt Regional Landfill. Republic Services operates a RCRA Subtitle D solid waste landfill near Roosevelt, Washington.

Columbia Ridge Landfill. Waste Management operates a RCRA Subtitle D solid waste landfill near Arlington, Oregon.


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Chemical Waste Management (Hazardous Waste Facility). Waste Management operates a RCRA Subtitle C/TSCA solid and hazardous chemical waste management facility near Arlington, Oregon.

Proposed landfills for RA will be identified through the 60% and 95% Design for EPA approval.

Waste material placed in RCRA Subtitle D landfills is normally required to pass the Paint Filter Test (EPA Method 9095B) demonstrating that there are no free liquids present in the material. However, both the Roosevelt Regional Landfill and Columbia Ridge Landfill have exclusions from the requirements of the Paint Filter Test for dredged material, allowing wet material to be delivered to the landfill. This can reduce the scope of conditioning required for landfilling of dredged material.

Sediment analytical results from RM11E SMAs were reviewed for waste designation purposes. Existing sediment data were compared to applicable waste disposal regulations and practical disposal options for excavated and/or dredged material as discussed below.

Toxic Substance Control Act

TSCA regulates PCB-containing material at greater than or equal to 50 milligrams per kilogram (mg/kg) (40 CFR Part 761). The PCBs at RM11E are not in a liquid form and have concentrations in sediment well below the TSCA regulatory limit, and are not considered to be TSCA-regulated wastes. The material does not qualify as TSCA regulated waste for any contaminants.

State of Oregon Additional Hazardous Wastes OARs regarding hazardous waste criteria (OAR 340-101-0033(2)) specify that residue─including, but not limited to, manufacturing process wastes and unused chemicals that are present in specified high-level concentrations (e.g., ≥3 or ≥10 percent by weight, depending on substance), and residues that have been spilled onto land or water at the same high concentrations─are considered additional state hazardous wastes. Material in the RM11E Project Area does not meet those criteria and, therefore, would not be designated as additional state hazardous wastes.

Listed Hazardous Waste Sediment removed from the RM11E Project Area would not be designated as “Listed Waste” as defined by RCRA. The RCRA regulations prescribe a list of specific wastes from common industrial and manufacturing processes. These listed wastes are divided into four categories, F, K, P, and U (40 CFR 261.31 through 261.33). Dredged materials that will be generated at the RM11E Project Area would not list as hazardous for any of the four categories:

F – Does not list as a hazardous waste from a non-specific source, such as spent solvents used for cleaning or degreasing.

K – Does not list as a hazardous waste from a specific source, such as petroleum refining or veterinary pharmaceuticals.


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P – Does not list as discarded, unused commercial chemical product, off-specification species, container residues, and/or spill residues thereof.

U – Is not an unused discarded commercial chemical product.

Characteristic Waste Characteristic waste is defined as waste that exhibits one or more of the following characteristic properties: ignitability, corrosivity, reactivity, or toxicity (40 CFR Part 261, Subpart C). Constituents at the RM11E Project Area have the potential to exhibit only the toxicity characteristic depending on individual constituent concentrations. Analytical data from site sediment samples were compared to Table 1 of 40 CFR 261.24 for each constituent and corresponding hazardous constituent concentration threshold limits.

Current data show a limited number of samples analyzed for total chromium and lead that—using the 20 times rule for total concentrations39 as a screening tool—might individually exceed RCRA toxicity characteristic regulatory levels using EPA Method 1311 - Toxicity Characteristic Leaching Procedure (TCLP). The TCLP regulatory level for both lead and chromium is 5 milligrams per liter (mg/L). Therefore, the 20x guideline for both is a total chromium or lead concentration of 100 mg/kg. Two chromium samples (RM11E-G026 and RM11E SL022) and several lead samples exceeded the 20x guideline; however, concentrations observed in the remainder of the RM11E Project Area are relatively low by comparison to those samples, and representative samples of the material to be dredged would likely not exceed the TCLP threshold to be regulated as a hazardous waste. Sediment in the SMAs will be further sampled for RD and waste characterization purposes, during which time TCLP analyses could be performed on composite samples (if any) that exhibit concentrations exceeding the 20x screening threshold for total metal concentration.

Pesticide Disposal DEQ provides guidance on disposal of pesticide residues. DEQ’s guidance exempts “pesticide containing material,” including soil (sediment) where pesticides are present due to the use (offsite or upstream) as intended by the manufacturer and as described on the label instructions from being classified as pesticide residue. This exemption is applicable to sediment at the RM11E Project Area because the presence of pesticides is generally the result of deposition from upland runoff:

OAR 340-100-0010(3)(j)(B). Pesticide residue does not include pesticide-containing materials that are used according to label instructions, and substances such as, but not limited to, treated soil, treated wood, foodstuff, water, vegetation, and treated seeds where pesticides were applied according to label instructions. Pesticide residue does not include wastes that are listed in 40 CFR Part 261 Subpart D or that exhibit one or more of the characteristics identified in 40 CFR Part 261 Subpart C.

No pesticides were found to be present at concentrations that designate them as hazardous when compared to the toxicity characteristic regulatory levels.

39 The TCLP rule of 20 allows for total concentration analysis to be used in lieu of the TCLP extraction procedure by multiplying the regulatory limit by 20 (or dividing the total constituent analysis by 20) to compare. The method is derived from the 20:1 liquid-to-solid ratio used in the TCLP procedure.


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Wood Piling Disposal Treated wood pilings are not classified as hazardous waste in 40 CFR 261.4(b)(9) per the following sections:

40 CFR 261.4(b) – Solid wastes that are not hazardous wastes.

The following solid wastes are not hazardous wastes:

(9) Solid waste which consists of discarded arsenical treated wood or wood products which fails the test for the Toxicity Characteristic for Hazardous Waste Codes D004 through D017 and which is not a hazardous waste for any other reason if the waste is generated by persons who utilize the arsenical-treated wood and wood product for these materials’ intended end use.

Wood products treated solely with arsenical preservatives are excluded from hazardous waste regulation when disposed of by the end user regardless of TCLP results for Waste Codes D004 through D017. TCLP testing on pentachlorophenol ("penta", Waste Code D037) and creosote-treated wood generally do not fail the toxicity characteristic. Wood products treated with preservatives that do not contain TCLP constituents are not a hazardous waste under the toxicity characteristic. Further support can be provided during RD if required.

RD Sampling Considerable sediment chemistry data already exist for Target Material. RD sediment sampling will provide additional sediment chemistry data that will be used to confirm the initial determinations above, and to profile the dredged material for acceptance by selected landfills. The program may include TCLP sampling and analysis for chromium and lead, and will be informed through consultation with the selected landfills before collection of additional sediment data. Physical properties of the sediment will be used to inform handling requirements for dewatering and conditioning, transload, and landfilling.

6.2.8 Sediment Transload and Transport Transload options for the RM11E Project Area include: existing commercial transload facilities, future commercial transload facilities, and project-specific transload facilities. The RM11E Group intends to coordinate with EPA, other early action parties, and other stakeholders on potential transload facilities for PHSS RA, including at the RM11E Project Area. The treatment of dredge water that is generated at transload facilities is discussed in Section 6.2.6.

Existing Transload Facilities Environmental dredging projects in PHSS currently use project-specific facilities in the greater Portland area to transload dredged material from barges to trucks for transport to landfills.

For large volume dredging projects, there are three potential transload facilities on the Columbia River for transfer of dredge material to upland landfills: the Waste Connections dedicated barge offloading facility near The Dalles, Oregon; Port of Morrow in Boardman, Oregon; and a potential facility at the SDS Lumber facility in Bingen, Washington, which would be the closest upriver facility, approximately 87 river miles from the RM11E Project


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Area. To make barge transport of the material up the Columbia River cost effective, it would be necessary that sediment dredged into onsite material barges be consolidated into larger barges for the push upriver to the transload site. The cost of the tugboat and crew time can make transportation of small volumes cost prohibitive. Dredged sediment would be transferred to larger barges before leaving the site. The transfer of sediment would require procedures be in place to prevent the loss of contaminated sediment into the river, and could include: tarps, plastic sheeting, and/or rigid deflectors between adjacent barges under the swing path of the equipment performing the consolidation.

At transload facilities, sediment is removed from barges, stockpiled, further dewatered and conditioned if necessary, and then placed into trucks or railcars for the haul to the appropriately licensed and permitted landfill. Conditioning of the sediment by the addition of absorption or drying additives may be required to achieve the appropriate moisture content and consistency for disposal and/or transportation. Any decanted free-standing water not absorbed by the conditioning process would be treated before discharge according to treatment specifications to be developed during RD.

Offsite transload facilities are generally operated by the landfill that they are serving, and transload operations would be responsible for having procedures in place that prevent the loss of contaminated sediment to the surrounding area and from entering the waterway. Construction improvements would likely be necessary at most offsite transload facilities to accommodate the offloading of large volumes of sediment, and would require additional permits to be obtained by the facility receiving the material.

Future Transload Facilities It is likely that additional transload facilities will be developed to accommodate the 3 million cubic yards of dredging projected for PHSS. An example of this is the City of St. Helens’ (Oregon) plan to repurpose its wastewater treatment lagoon—located on the Columbia River 23 river miles downstream from the center of PHSS—into a transload and confined sediment disposal cell (MFA and ECONW, 2016). This facility would need to be operational and appropriately licensed and permitted to accept the dredged material from the RM11E Project Area.

The major regional landfills are also believed to be evaluating the development of riverfront barge transload to rail facilities, possibly within PHSS, to move dredged material by rail to their regional landfills up the Columbia River. The availability of such facilities for the RM11E RA will depend on the timing of the development and availability of the facilities.

Project-Specific Transload Facilities Currently, there are no plans to develop a project-specific RM11E transload facility. However, if commercial transload facilities are not practically available at the time of the RM11E RA, then project-specific transloading facilities would need to be developed at the RM11E waterfront or contracted at an offsite location. The facility would be designed as a component of the RD. Transload options will be considered during RD and likely selected during the RA contracting process.


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Transportation Methods Multiple forms of transportation of dredged material from the RM11E Project Area are feasible, including barge, railcars, and trucks. The mode of transportation is a function of the facilities available at each individual landfill. Smaller volume projects could be served by truck transport from a project-specific transload facility to a local area landfill. Transload facilities developed to serve the PHSS project could use barge and rail transport.

Current and potential future transload facilities and operations associated with the landfills identified in Section 6.2.7 are as follows:

RCRA Subtitle D Solid Waste Landfills

Hillsboro Landfill. Onsite transload to trucks as follows:

o Dredged sediment would be conditioned and loaded into trucks from a transloading area.

o Trucks may be required to operate with sealed tailgates or be lined with plastic if transporting wet material to prevent drippage and then covered with a tarp when full.

o Trucks would remain on clean paved surfaces or exit the loading area by way of a wheel wash to control track-out before they proceed on a predetermined truck route to the Hillsboro Landfill.

Wasco County Landfill. Truck transport for smaller volumes or barge transportation to Waste Connections’ transload site in The Dalles, Oregon, as follows:

o Dredged sediment would be loaded into barges within the RM11E Project Area until full, then moved to a designated in-water location for conditioning and consolidation into a larger barge for the push upriver.

o Sediment would be offloaded at the Waste Connections’ transload facility and conditioned as required.

o Conditioned sediment (absent free water) would be loaded into trucks for transport to Waste Connections’ landfill near The Dalles, Oregon.

Roosevelt Regional Landfill. Republic Services operates a solid waste landfill near Roosevelt, Washington. While truck transport is available for smaller volumes, two modes of transportation are possible for larger volumes of dredge material:

o Barges of dredged material from the RM11E Project Area would be moved to a yet-to-be-established waterfront transload facility, possibly in PHSS, where it would be offloaded into lined 20-ft-long open-top containers on railcars for transport to the Roosevelt Regional Landfill. Republic Services does not usually require conditioning of dredge material before shipping in waste containers.


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o Barges of dredged material from the RM11E Project Area would be moved to a designated in-water location for consolidation into a larger barge for the push upriver:

Sediment would be barged to potential transload site in Bingen, Washington (not fully operational at this time), and conditioned as required.

Conditioned sediment (absent free water) would be offloaded from barges into trucks or railcars and transported approximately 72 miles to the Roosevelt Regional Landfill.

Columbia Ridge Landfill. Waste Management operates a solid waste landfill near Arlington, Oregon. While truck transport is available for smaller volumes, two modes of transportation are possible for larger volumes of dredge material:

o Barges of dredged material from the RM11E Project Area would be moved to a yet-to-be-established waterfront transload facility, possibly within PHSS, where it would be conditioned as required and offloaded onto lined gondola railcars for transport to the Columbia Ridge Landfill. Waste Management usually requires dredged material to be conditioned before shipping in gondola cars.

o Barges of RM11E dredged material would be moved to a designated in-water location for consolidation into a larger barge for the push upriver:

Sediment would be barged to the Port of Morrow in Boardman, Oregon, and conditioned as required.

Conditioned sediment (absent free water) would be offloaded from barges into trucks and transported approximately 40 miles to the Columbia Ridge Landfill.

RCRA Subtitle C/TSCA Solid and Hazardous Waste Landfill

Chemical Waste Management (Hazardous Waste Facility). Waste Management operates a Subtitle C/TSCA solid and hazardous chemical waste management facility near Arlington, Oregon.

o Sediment that is designated as Characteristic Hazardous Waste based on TCLP testing (none currently expected in the RM11E Project Area).

o For smaller volumes:

Dredged sediment would be conditioned and loaded into trucks from a transloading area.

Trucks may be required to operate with a sealed tailgate or be lined with a sealed plastic liner and then covered with a tarp when full.


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Trucks would remain on clean paved surfaces or exit the loading area by way of a wheel wash to remove mud before they proceed on a predetermined truck route to Chemical Waste Management.

The selection of a transload facility and associated transportation mode(s) for the RM11E Project Area will be determined on the basis of the scope of the dredging project as well as the characteristics of transload facilities and landfills available at the time of the RA.

6.2.9 Source Materials Granular capping/residuals management cover material will likely be sand, or sandy gravel for placement on flatter areas of the riverbed, or angular rock for placement on the steeper slopes of the RM11E Project Area. The material will be procured from sources that are verifiably clean from contamination. Based on the current ~10-acre footprint of the RM11E SMA, approximately 20,000 to 25,000 cubic yards of material would be needed if a nominal 1-ft-thick cover were placed over the SMA. The actual extent of cover will be established during RD. Depending on the requirements of the Water Quality Certification under Section 401 of the CWA, the material may need to be washed to limit turbidity generated during placement.

Clean fill material may be procured from multiple sources and will require sampling for physical and chemical properties that meet project design criteria, and receive review and approval from EPA before being placed at the site. Possible sources include:

Columbia River mid-channel dredge sand from active maintenance dredging projects.

Upland sources of stockpiled Columbia River dredged sand.

Stockpiled sand and crushed gravels from various quarries such as CalPortland’s Santosh Aggregate plant in Scappoose, Oregon

Several methods are available for material to be delivered to the site, and the preferred method is generally left to the contractor to select; however, there can be advantages associated with controlling traffic onsite and offsite, should there be concern with traffic or accessibility. A few viable delivery mechanisms for import material are:

Source the material from a quarry or sand and gravel company that can load and barge material to the project site:

o Northwest Aggregates, Co. (dba CalPortland) operates the Santosh Aggregate Plant in Scappoose, Oregon. From this location the company mines aggregate and loads material barges that can be pushed the short distance upriver to the RM11E Project Area.

o RIS&G owns several locations with barge-loading capabilities, and frequently mines sand and gravel from dredging operations on the Columbia River and its Columbia River upriver pit in Wishram, Washington.

o Knife River operates a dock and barge loading operation in St. Helens, Oregon.


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Set up or use an existing berth within the RM11E Project Area to truck in fill material and transload it onto material barges.

Coordinate with an active maintenance dredging project to deliver full material barges to the project site directly from the dredging site.

Sourcing for activated carbon and other amendment materials, if used, will occur during RD depending on the nature of the application.

Sampling for physical and chemical properties will be undertaken before approving material intended for onsite placement. Granular fill and activated carbon materials will be screened against the ROD CULs and the Sediment Evaluation Framework for the Pacific Northwest (Northwest Regional Sediment Evaluation Team Agencies, 2016). Clean source statements and other information will be provided indicating the source of the material and to verify that the material is suitable for its intended use. Imported material screening procedures, criteria, and testing frequency will be developed during RD, and will stipulate the required intervals to sufficiently characterize all material to be brought onsite.

6.2.10 Green Remediation Green remediation practices are identified in Section 14.2.12 of the ROD. There are opportunities to implement green remediation practices during the RA in the RM11E Project Area through consideration of remedial technologies that:

Use renewable energy and energy conservation and efficiency approaches, including Energy Star equipment.

Use cleaner fuels, such as low-sulfur fuel or biodiesel, diesel emissions controls and retrofits, and emission reduction strategies.

Use water conservation and efficiency approaches including Water Sense products.

Use reused or recycled materials within regulatory requirements.

Minimize transportation of materials and use rail or barges rather than truck transport to the extent practicable.

Identification of technologies that are considered consistent with green remediation practices will be performed during RD and the selection of representative technologies, including consideration of relative costs, will be further evaluated.

6.3 Step 6: Consistency with the ROD The technologies identified in Steps 1 through 4 as being compatible with facility and physical site conditions are evaluated in this section for consistency with the ROD design criteria.

Removal or Containment of Target Material Through application of the technologies discussed above, the RA at the RM11E Project Area will address known Target Material, either through dredging (removal) or capping (containment). Accordingly, the technologies being carried forward into RD will be


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consistent with the ROD. As discussed above, specific locations in RM11E Project Area to be targeted for dredging vs. capping may vary somewhat from the ROD Technology Application Decision Tree where necessary to accommodate site-specific conditions.

Capping The identified capping technologies have been developed to be consistent with the design requirements of the ROD. During RD, locations on the site will be identified as areas to receive a cap. When specific capping locations are identified, site- and condition-specific caps will be designed of sufficient thickness and composition to contain Target Material and COCs that could desorb from Target Material, as well as with sufficient armoring to remain in place when subjected to expected erosive forces. To comply with the ESA and Section 404 of the CWA, caps will be designed to limit adverse effects on in-river and riparian habitat and loss of shallow water habitat.

While complying with design criteria, the identified capping technologies may vary from the programmatic remedy described in the ROD. For example:

Conventional capping is not practical in some portions of the RM11E Project Area, including areas at or behind docks, or on the open slopes near the docks. Hybrid capping, covering, and dredging technologies have been identified for further evaluation during RD. Additional capping or covering technologies will likely be evaluated as the RD progresses.

The final grade following capping after any dredging may not match the bed elevations before remediation because of the site constraints to maintain stable slopes and not adversely impact existing upland industrial operations. The final slopes would be designed to comply with the requirements of the ESA and Section 404 of the CWA.

The locations where backfilling to grade is not practical or necessary will be developed during the Alternatives Evaluation and through 60% Design.

EPA’s seismic recommendations for capping at the PHSS will be taken into consideration as RD continues to develop at RM11E.

Dredging The identified dredging technologies will be designed to be consistent with the requirements of the ROD, including: placing a residual management layer following dredging; removing or temporarily relocating structures, where appropriate, to facilitate dredging; removing and/or managing debris in place, as needed to access Target Material; applying engineering and operational controls as necessary to limit releases to the water column; and selecting disposal locations based on waste characterization and applicable disposal regulations.

As is the case for capping, the final grade following dredging may not match the bed elevations before remediation because of the site constraints to maintain stable slopes and not adversely impact existing upland facility operations. The final slopes would be designed to comply with the requirements of the ESA and Section 404 of the CWA.


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In Situ Treatment The addition of activated carbon in capping materials or direct placement to manage porewater, where appropriate, will be designed on the basis of site- and condition-specific factors, consistent with ROD design requirements. Application of a surface layer of AquaGate® (or another in situ treatment product) is a potential remediation technology, particularly in areas of thin deposits of Target Material, such as behind the or under Cargill main dock. Further evaluation will be performed during RD to determine the effectiveness and viability of in situ treatment at RM11E.

Enhanced Natural Recovery Other than application of a residual management layer of sand following dredging, ENR has not been identified as a component of the currently identified remedial technologies for the RM11E Project Area. Should ENR become a component through the RD process, then it would be designed to be consistent with the ROD.

Riverbanks The identified technologies include consideration of laying back and/or stabilizing the river bank adjacent to SMAs to mitigate potential bank failure during or following remediation. These riverbanks will be further characterized during RD and addressed (i.e., stabilized or remediated) consistent with the ROD and where they pose a risk of recontamination to remediated areas through erosion.


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7. Performance Standards and Monitoring

The BODR is an early step in the RD process. This section presents initial concepts of RA performance standards and associated points of compliance that will be used to verify completion of the active remediation in the RM11E Project Area. Performance standards are developed to assess the effectiveness of the remedy through performance monitoring. The RM11E Group anticipates collaborating with other Portland Harbor parties and EPA during RD to develop and incorporate general PHSS-wide performance standards that can be applied to remediation technologies (such as dredging and capping). Those standards will be adapted as appropriate during RD for site-specific conditions and RAs at RM11E in compliance with the RM11E AOC and SOW.

7.1 RA Performance Standards and Monitoring RA performance standards represent the conditions to be maintained during remedial construction (e.g., water quality) and the conditions to be achieved at completion of the active remediation component of the RA (e.g., surface sediment concentrations). The standards include both physical and analytical criteria as well as designated points of compliance.

The initial discussion of performance standards and monitoring for RM11E incorporates application of the RDMs described in Section 6 as part of the proposed RA to limit the environmental exposure from dredging.

7.1.1 Water Quality During RA Water quality performance standards, points of compliance, and monitoring requirements (including parameters, locations/depths, frequency/schedule, background surveys, visual monitoring, and equipment) will be developed during RD to achieve substantive compliance with Oregon’s WQS, similar to a Water Quality Certification under Section 401 of the CWA. The monitoring will include turbidity measurements as well as potential sampling and analysis of PCBs. It will be defined in the Project Water Quality Monitoring Plan (WQMP). The details of water quality monitoring will be developed in a Water Quality Monitoring Plan (WQMP) later in Design, according to the schedule set forth in the RDWP, to meet EPAs objectives while being adapted to the conditions specific to RM11E.

Water quality measurements will be made at a point of compliance, or compliance boundary to be located 300 ft downstream from in-water RA activity. Water quality parameters will be measured at multiple depths in the water column (e.g., at 1/3 and 2/3 water column depth). The WQMP will outline the frequency of monitoring as well as corrective actions to be initiated should performance standards be exceeded at the compliance boundary. For example, recent DEQ Section 401 Water Quality Certifications for dredging have included activity restrictions based on turbidity levels as follows:

0-5 NTUs above background – No restrictions.


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5-29 NTUs above background – Work may continue for a maximum of 4 hours. If turbidity remains 5-29 NTUs above background, stop work and modify methods. Work may resume when turbidity is 0-5 NTUs above background.

30-49 NTUs above background – Work may continue for a maximum of 2 hours. If turbidity remains 30-49 NTUs above background, stop work and modify BMPs. Work may resume when turbidity is 0-5 NTUs above background.

50 NTUs or more above background – Stop work immediately and inform DEQ.

A modified version of these restrictions may be appropriate for placement of clean RMC or capping materials. As discussed in Appendix C, studies indicate that adverse effects to juvenile Chinook salmon would not occur without more significant elevation of turbidity. Based on the information provided in Appendix C, a single value turbidity threshold of 50 NTUs over background at the point of compliance would be appropriate during placement of clean RMC and cap materials. Using this turbidity standard for RMC and cap placement would allow for a more continuous and expeditious completion of RAs.

7.1.2 Dredging and Close Out The RM11E Group has reviewed the Site Dredge and Cover Design, Implementation, Verification, and Closeout Approach (Anchor QEA, 2018) that was developed for the Gasco site in Portland, Oregon, and recently approved by EPA. The approach includes the following components that may be applicable to RM11E and are included here for further consideration during development of the 30% Design. The details of dredging and associated closeout measures will be developed as part of 60% Design and a RA QAPP to meet EPAs objectives while being adapted to the conditions specific to RM11E.

Dredge Design Perform a robust sediment characterization program, including coring, to establish

the horizontal and vertical extent of Target Material.

Prepare a 3-dimensional (3D) dredge prism of Target Material for input into the dredge positioning system.

Develop site-specific, constructible Dredge Management Units (DMUs) for implementing the RA.

Dredging Implement project-specific RDMs (see Section 6.2.5) to limit generated residuals and

resuspension of sediment into the water column, while maintaining production rates to support timely removal of Target Material.

Post-Dredge Verification Verify completion of dredging in each DMU by bathymetric surveys to confirm

removal of Target Material to the pre-defined 3D dredge prism. After the elevation is verified, dredging in a DMU is complete. If the target elevation is not reached, perform additional dredging to remove high spots and confirm that the required target elevations are achieved.


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Post -dredge confirmation sampling will be completed to verify that Target Material has been removed. The scope of the confirmation sampling program will be established in cooperation with EPA as part of the RA QAPP based the results of the RD sampling programs. The certainty/uncertainty of extent of Target Material established through the RD sampling programs is one of the primary factors that will be considered. Post-Dredging Residual Layer

Operationally define the post-dredging residual layer as the top 6 inches below the post-dredging surface. Periodic monitoring will provide data on the thickness of post-dredge residuals during construction and provide a basis for modifying the operational definition as appropriate, to be detailed in the RA QAPP.

Collect post-dredging samples of the residual layer at the rate of five samples per acre within a DMU. For smaller DMUs the samples will be collected at a rate of:

o Four samples for areas of 0.75 to less than 1 acre o Three samples for areas of 0.5 to less than 0.75 acre o Two samples for areas less than 0.5 acre

Composite all residual layer samples within a DMU for analytical testing.

Chemical analysis of generated residuals samples will be limited to PCBs where PCBs are the predominant compound in a DMU, which is the majority of the RM11E Project Area. The basis for including other compounds in the analysis of generated residuals will be established during the 30% Design.

The acceptable concentration of PCBs in the residual layer is based on achieving an average concentration in the RMC layer that is at or below the CUL. The Gasco site acceptable concentration is called the RAO 5 CUL Protective Threshold Concentration.

Based on a 2013 USACE report titled “Review and Recommendations on Dredge Release and Residuals Calculations from the Portland Harbor Draft Feasibility Study”, the lower 2 inches of the 1-ft. RCM layer will be mixed with the underlying residual layer at a conservatively estimated COC concentration of 15 percent of the COC concentration in the residual layer, with the upper 10 inches of the RMC layer remaining clean. Based on this the residual layer concentration that results in an average RMC concentration at the CUL is calculated as [CUL / (0.15 x (2/12))] = 40xCUL.

PAHs are the dominant compound at the Gasco site, with a CUL based on ecological exposure. At the RM11E Project Area, PCBs are the dominant material with the 9 ug/kg PCB sediment CUL based on background sediment concentrations. Accordingly, using the 40xCUL formula from the Gasco site, the PCB Protective Threshold Concentration at RM11E would be 360 ug/kg (40 x 9 ug/kg = 360 ug/kg). The PCB Protective Threshold Concentration at RM11E will be determined in the RA QAPP.


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Residual Management Cover (RMC) and Close Out An initial 6-inch nominal thickness RMC layer will be placed in a DMU within a

couple of weeks after completing DMU post-dredge verification by bathymetric survey and confirmation of PCB concentrations below the Protective Threshold Concentration in the residuals layer.

If the PCB concentration in the residuals layer is determined to be above the Protective Threshold Concentration, then the archived discrete samples would be analyzed in that DMU. Additional measures will be applied to individual areas represented by the associated discrete samples of concern rather than the entire DMU. The additional measures, such as additional RMC placement, if needed, will be selected in consultation with EPA based on the conditions at the time in the DMU.

A final 6-inch nominal thickness RMC layer will be placed later in the project, either at the end of the construction season, or the end of active remediation at the RM11E Project Area, to be determined during RD.

The RD coring program will be implemented to sufficiently define the extent of Target Material for design of the dredge plan. Because removal of the material identified in the dredge plan will be confirmed through the post-dredge bathymetric survey the post-dredging sampling program at the RM11E Project Area may not include sediment coring. The details of dredging and associated closeout measures will be developed as part of 60% Design and a RA QAPP to meet EPAs objectives while being adapted to the conditions specific to RM11E.

7.1.3 Residual Management Cover Sand cover will be placed as soon as practical following dredging in a DMU and following multiple steps to be completed before initiating sand placement: a post-dredging bathymetric survey; review of the bathymetric survey to confirm adequate removal of the Target Material; collection of post-dredging sediment samples; laboratory analysis of the samples; interpretation of the results; submittal of results to EPA, and; concurrence from EPA to proceed with placement of sand cover in the DMU. Once approval to place sand cover in a DMU is received, there may still be more activities to complete before initiating sand placement: advancing the dredging equipment far enough away from the DMU to provide the required equipment clearance between the dredge and the derrick placing the sand so that both may operate safely; coordination with active terminal vessel traffic; and dredging of the areas adjacent to the DMU to avoid placing sand onto Target Material in the adjacent DMUs. Once initiated the actual placement of the sand cover may take several days to complete based on the size and configuration of the DMU. The time to complete placement of sand cover for the Boeing Plant 2 project on the Duwamish Waterway took from a week to a month following dredging in a DMU depending on the site conditions and constraints, with the longer times associated with DMUs where dredging was completed in adjacent DMUs before placing sand in the DMU. The details of practical sand cover placement will be developed in RD and presented as part of 60% Design.

Sand imported for use in the RMC layer will, to the extent practicable, be verifiably free from COCs in excess of the CULs for River Bank Soil/Sediment in Table 17 of the ROD and screening levels provided in the Sediment Evaluation Framework for the Pacific Northwest


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(Northwest Regional Sediment Evaluation Team, 2016). Imported material screening procedures, criteria, and testing frequency will be developed during RD.

Sandy material placed on the relatively steep slopes at RM11E will likely slough downslope, or be displaced due to oversteepened slopes, river currents, and/or wave action; therefore, RMC material placed on slopes in the RM11E Project Area will likely need to be gravel sized or larger angular rock for stability. Specific grain size and material characteristics will be developed as part of RD. To limit the generation of excess turbidity during placement, RMC will need to be mostly free of silt and clay.

RMC will generally be placed in 6-inch-thick nominal lifts. Rather than attempting to measure the thickness of relatively thin layers of granular material on the riverbed, the performance standard for the RMC placement will be a weight-based application rate as follows:

Convert the volume of material to be placed per acre into tons based on the unit weight of the material. For example, based on a unit weight of 1.6 tons/cubic yard, the application rate for a ½ ft nominal thickness would be ~1,300 tons/acre40. The application rate will be the physical performance standard for placement of the residual management layer. Monitoring will involve tracking the tons delivered and placed (such as with barge displacement readings or conveyor belt scales) over a known area, as well as using electronic positioning systems on the delivery system to confirm full coverage over the DMU. Periodic construction quality control samples could be collected during RMC placement with “rain buckets” placed on the bed to collect RCM as it is placed, with the bucket brought to the surface following placement to measure the depth of RCM collected in the bucket.

The details of RMC placement and associated close out methods, including QC samples, will be developed as part of 60% Design and a RA QAPP to meet EPAs objectives while being adapted to the conditions specific to RM11E.

7.1.4 Capping Sand imported for capping will, to the extent practicable, be verifiably free from COCs in excess of the CULs for River Bank Soil/Sediment in Table 17 of the ROD and screening levels provided in the Sediment Evaluation Framework for the Pacific Northwest (USACE et al., 2018). Larger material (>gravel) will be sourced from commercial, native quarried sources. Imported material screening procedures, criteria, and testing frequency will be developed during RD. To limit the generation of excess turbidity during placement, the material will need to be mostly free of silt and clay. The size, thickness, location, and components of various capping layers including grain size and material characteristics, as well as testing frequency, will be developed as part of RD.

Because of the potential low strength properties of some of the existing surface sediment, consolidation of that material will likely occur upon placement of a cap, resulting in settlement of the surface of the cap. Verifying cap thickness by multibeam bathymetry alone therefore would be ineffective at determining the actual cap thickness. Placement of cap material will be tracked during construction in several ways including monitoring of 40 [(0.5’ * 1 acre) * (1,613 cubic yard/acre-ft.) * (1.6 tons/cubic yard)] = 1,290 tons per acre


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application rates and coverage (as described above for RMC), possible pilot studies during initial stages of RA for spread pattern and thickness verification, observation of construction methods, GPS positioning to record bucket location and spread, and multibeam bathymetry.

Gravity or direct push coring devices would not penetrate armor layers over caps and could be of limited effectiveness for cap monitoring. Cores can be used to effectively verify constructed thickness of the chemical isolation layer before placement of the armor layer. Depending on the grain size of the material being placed periodic construction quality control samples could be collected, such as with “rain buckets” as described for RMC placement. The capping confirmation program, including QC sampling and the effectiveness and use of rain buckets, will be developed as part of 60% Design and a RA QAPP to meet EPAs objectives while being adapted to the conditions specific to RM11E.

7.2 Baseline and Long-Term Monitoring This section identifies initial post-remediation baseline and long-term monitoring concepts specific to the performance of the RM11E Project Area RAs.

7.2.1 Baseline SWAC The collection of randomized or spatially-representative surface sediment samples across the RM11E Project Area following RA to establish baseline PHSS SWACs may be problematic or not possible. It is likely that the RMC placed on the slopes following dredging will be gravel sized or larger angular rock for improved stability. Likewise the surface layer of most, if not all, caps will be armored to protect against erosion. Given this, few areas of the remediated SMA footprint outside of the Navigation Channel and FMD Regions will have sufficient sediment to sample and analyze for COCs following active remediation. COC concentrations of zero could be assumed for the calculation of SWACs where gravel/rock is present at the surface. The details of immediate post-RA baseline sampling and monitoring will be developed in RD once the scope and configuration of the RA is defined. The final approach to calculating SWACs for the site and RM11E Project Area, including areas of gravel/rock cover, will be developed as part of EPA’s long-term monitoring plan for PHSS.

7.2.2 Caps Long-term monitoring of the capped areas will be designed to confirm the physical integrity and continued effectiveness of the caps, and may include bathymetric surveys, and visual inspections at defined transects (i.e., divers or other video technologies to document the condition of submerged caps). Physical integrity monitoring would be completed periodically. The RDWP will consider monitoring once per year during years 1, 3, and 5 after completion of the RM11E Project Area RA, and then at 5-year increments thereafter. Additional integrity monitoring would also occur following extreme natural or other human-caused events that have the potential to damage any portion of capped areas. The details of cap monitoring and maintenance will be set forth in a long-term monitoring and maintenance plan to be developed during RD.


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7.2.3 Habitat Mitigation Areas Should habitat mitigation be required, it would either be constructed as part of the RM11E Project Area RA, or purchased from a mitigation bank. A long-term monitoring program would be established for habitat constructed as part of the RM11E Project Area RA to confirm performance of the project relative to the intended habitat functions and services. It would be completed periodically after completion of the RM11E Project Area RA and stopped after the habitat is well established and functioning as intended. If the RM11E Project Area includes habitat mitigation, details of habitat monitoring and maintenance will be set forth in a long-term monitoring and maintenance plan to be developed during RD.


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8. Design Studies

Design studies will be performed as part of RD and will be detailed in the RDWP. Based on the outcome of this BODR, proposed design studies are organized as follows:

RD Sediment Characterization

RD Technical Studies and Alternatives Evaluation

Additional RD Investigations

8.1 RD Sediment Characterization Purpose: Additional sediment data are required to more fully define the extent of the RM11E SMA footprint and the nature and extent of Target Material for RD.

RD sediment characterization will be undertaken in two phases. The first phase will update the RM11E SMA, better characterize the vertical extent of Target Material, and characterize conditions in portions of the adjacent riverbank in support of the alternatives evaluation. The second phase of sediment sampling will occur after the preferred alternative is established and will consist of sediment cores and/or borings to fill remaining data gaps and provide engineering parameters at specific locations to be capped and dredged. The sampling programs will be detailed in sampling and analysis plans (SAPs) for EPA review and approval, with the findings presented in reports to be submitted for EPA review and approval.

8.1.1 Phase 1 RD Sediment Characterization The first phase of sampling will be performed in conjunction with the initial technical studies to address the following objectives:

Update RM11E SMAs (Section 2.7.1). Although the currently defined SMAs are useful in estimating the areas warranting active remediation, some data are more than 9 years old and changes in surface sediment concentrations may have occurred due to natural recovery or other processes. As such, RD surface sediment sampling will be completed to refine the lateral extent of relevant PHSS COCs above RTs to support updating the extent of active remediation areas at RM11E.

Vertical Extent of Target Material (Section 2.7.3). The DOI has not been determined in some areas. RD sampling will be conducted to provide added definition of the vertical extent of Target Material as needed for the alternatives evaluation. Sampling technologies will be selected to provide the vertical accuracy appropriate for RD. Coring/boring will be designed with the objective to extend the full depth of contamination plus an additional 2 ft of underlying non-Target Material (concentrations less than RTs). Sampling to delineate depth of contamination will be detailed in the RD QAPP.


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Characterize the RM11E Riverbank Areas (Section 2.7.2). Upland-based RD borings will be completed at riverbank locations adjacent to SMAs to characterize the COCs in the bank where needed to protect the in-water remedy and provide engineering properties to address bank stability, bank layback, and bank capping if needed.

At this time, the RM11E Group expects that the Phase 1 subsurface sediment data will be used to supplement existing data sets. However, the final proposed use of Phase 1 sampling to supplement or replace available surface sediment data is yet to be determined and will be provided in the RDWP and Phase 1 QAPP.

8.1.2 Phase 2 RD Sediment Characterization The second phase of RD sediment characterization will be initiated after the preferred alternative has been established including the expected lateral extent of dredging and capping technologies. The program will consist mainly of subsurface sediment sampling. The sampling program will be developed to address the following objectives:

Second Phase, Vertical Extent of Target Material within SMA. A second phase of sediment sampling will be conducted with closer sample spacing in areas targeted for dredging to aid in the development of a 3D dredge prism. As is the case for the Phase 1 program, sampling technologies will be selected to provide the vertical accuracy appropriate for RD. Coring/boring will be designed to extend the full depth of contamination plus an additional 2 ft of underlying non-Target Material (concentrations less than RTs).

Character of Target Material for RD. RD sampling will be conducted to obtain data for area-specific preferred remediation technologies at a data density appropriate for RD. The RD sediment characterization will have different objectives for areas to be dredged (i.e., dredge material characteristics and dredge prism development) and areas to be capped (i.e., COC containment and armoring). The sediment data will also be used to profile material for disposal and provide engineering characteristics for dredging, dewatering, water treatment, and capping design (e.g., chemistry, grain size, plasticity, specific gravity of solids, water content, total organic carbon, porosity, sediment strength, consolidation characteristics, hydraulic conductivity based on grain size, and bulk density).

8.2 RD Technical Studies and Alternatives Evaluation Purpose: Technical studies are needed for selection of preferred technologies and approaches to implementing remediation for specific areas of RM11E, as well as for RD of those technologies.

As discussed in Section 6, site-specific constraints prevented the selection of a single remediation technology in this BODR for some portions of the RM11E Project Area, including the areas at, around, and behind the Glacier NW and Cargill main docks. An alternatives evaluation will be performed to refine and select implementable and cost-effective technologies for those portions of the RM11E Project Area that required further analysis. The RD technical studies needed to complete the alternatives evaluation will be conducted in parallel with the first phase of RD sediment characterization. The studies will


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evaluate the compatible ROD remediation technologies identified by this BODR (see Section 6.1.10) together with facility access and modification options to improve access to Target Material for RAs across the site.

The results of the alternatives evaluation and technical studies will be presented for EPA review and approval in a Preferred Alternative report before submittal of the 30% Design.

8.2.1 Compatible Remediation Technologies This BODR has identified ROD-consistent remediation technologies that are generally compatible with site conditions as presented in Section 6. The technologies are summarized below and SMAs where they are applicable are shown on Figure 8-1.

Dredging

Dredging is the primary technology for remediation in the Navigation Channel and FMD Regions and open slope areas.

o Dredging in the Navigation Channel can occur during the typical in-water work window without conflicts with facility operations.

o Dredging in FMD Region and open Intermediate and Shallow slope areas will need to be coordinated with facility operations, potentially during an expanded in-water work window.

Multiple Technologies at Structures

Multiple remedial alternatives will be evaluated for areas located beneath, behind, or around water front structures, potentially during an expanded in-water work window.

o Conventional capping is not viable under and behind docks or along most of the shoreline because of the constraints from over-steepened slopes, structural stability, future dredging requirements in the berth and FMD Region at the toe of those slopes, the height limitations of cantilevered toe walls, and spatial requirements for toe buttresses.

o Hybrid capping technologies, such as ACB mats or incorporation of the remnant piling into terraced walls, have been identified as potential remediation technologies beneath and behind docks, but are not yet established as implementable or effective in the RM11E Project Area and will be further evaluated during the alternatives evaluation and RD.

o Dredging is identified as a potential alternative in some areas around and below existing structures, depending on the access that can be established through facility modifications and expanded work windows, and resolution of structural and slope stability issues.

o In situ treatment, using products such as AquaGate®, has been identified for possible use in areas of thin deposits of Target Material, such as the area under and behind the Cargill main dock. Use of such products has not yet


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been demonstrated to be implementable or effective in the RM11E Project Area and will be evaluated during the alternatives evaluation and RD.

o If practicable, the oversteepened slopes along the site, including the upper riverbanks, may be required to be laid back or stabilized to mitigate the potential for bank failure during or after RA.

8.2.2 Facility Access and Modification Options for RA As discussed in Section 6, identification of specific remediation technologies in some portions of the RM11 Project Area requires consideration of impacts on and constraints imposed by existing facilities, operations, work windows, and access as well as sediment chemistry. The alternatives evaluation will consider different approaches to addressing these facility-related issues and constraints and identify the preferred alternative at each facility to further the RD. Possible approaches to be considered for addressing these issues at the multiple RM11E Project Area facilities are listed below.

Scheduling and duration of RAs at the RIS&G barge dock, the Cargill and Glacier NW main docks, as well as the area between Cargill and Glacier NW will be significantly affected by the length and timing of the in-water work window. If work is restricted to the typical work window, RA will take significantly longer to accomplish, and will have significantly greater impacts on facility operations and employment.

RIS&G Barge Dock

One remediation technology concept is identified: dredging with shoring (Figure 6-2). Temporary or permanent shoring will be proposed as needed to stabilize the block retaining wall and provide access to Target Material in the vicinity of the RIS&G barge dock.

Two potential approaches are identified for RA access:

o Start and stop RA around the RIS&G Terminal during the typical in-water window to allow terminal operations to continue uninterrupted (e.g., barges in and out), with associated multiple mobilization and demobilization efforts and extended time period for remedy completion.

o Relocation of the RIS&G sand and gravel operations during active remediation near its facility.

ODOT Outfall WR-306

One remediation technology concept is identified: dredging with bank layback / stabilization and possible block wall reconstruction (Figure 6-3). Reconstruction of the concrete block retaining wall will be proposed as needed to access Target Material in the vicinity of outfall WR-306.

To obtain construction access, the RM11E Group will need to coordinate the remediation of the area around outfall WR-306 with the remediation at RIS&G and Glacier NW. This approach may involve working in the area during the off-peak season depending on when access is available at RIS&G.


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Glacier NW Main Dock

Two remediation technology concepts are under consideration: dredging with bank layback/stabilization; and ACB mat capping and dredging (Figure 6-6.)

Several potential approaches are identified for RA access:

o Start and stop RA around Glacier NW’s River Street Terminal during the typical in-water work window to allow terminal operations to continue uninterrupted (e.g., ships and barges in and out), with associated multiple mobilization and demobilization efforts and extended time period for remedy completion.

o It may be possible to complete sediment remediation in the area north of Glacier NW’s main dock, including the area around the barge dock, during the typical in-water construction window. The tie-up bollards in this area may need to be relocated closer to the main dock for vessel stabilization.

o Remediation at the Glacier NW main dock during the off-peak December to February time frame while maximizing upland cement storage could possibly provide 2- to 3-week in-water work windows with no ship activity.

o The main dock consists of two sections: a north section and a south section. An alternative option for RA could involve temporarily removing the south section of the main dock to provide access to that section of the main dock and provide a means for remediation at and around the rest of the main dock. Under such a scenario, Glacier NW could temporarily shift all cement offload operations from the south section to the north section of the main dock. Removing the south section would extend offloading time due to having only a single offload point during remediation. This would require frequent shifting of the vessel (north and south) and spinning the vessel 180 degrees with a pilot, tug assistance, and re-tie up by longshoremen to offload the remaining cement. Moving operations to a single offload point would be most feasible during off-peak season due to reduced activity levels at the dock. After remediation is complete, reconstruction of the main dock would be required to re-establish full function to the Glacier NW River Street Terminal. The removed south section of the main dock either could be reconstructed north of the existing north section (essentially centering the main dock on the property) or rebuilt in its current location.

PacifiCorp Submarine Electrical Cable Crossing and Surrounding Area

Two remediation technology concepts are under consideration for the area between the Glacier NW main dock and Cargill main dock, including the area of the submarine electrical cable crossing: dredging with bank layback/stabilization, and engineered cap and dredging (Figure 6-7).


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RA access considerations include:

o Access for implementing either technology assumes that permanently relocating the submarine electrical cable crossing through the RM11E Project Area will be determined to be feasible so that the existing cable can be decommissioned, and RA can be completed without the risk of injury or of damage to the power supply to downtown Portland. If relocation and decommissioning are determined to be infeasible, or another option is identified, the RM11E Group will re-evaluate potential approaches to remediation in the cable crossing area.

o To ensure construction access in the area between the Cargill and Glacier NW main docks, the RM11E Group will also have to coordinate the remediation of the area with the remediation at the Glacier NW and Cargill docks. This approach may involve working in the area during the off-peak season at Glacier NW and/or Cargill.

Former Crane Tramway at Cargill and City OF43

Four remediation technology concepts are under consideration: diver dredging/dredging, ACB mat capping and dredging, remnant piling cap/dredging, and bank layback and dredging (Figure 6-8)

RA access considerations include:

o Demolishing the former crane tramway as needed to provide improved access to Target Material around the former tramway and to relocate OF43.

o Reconstructing OF43 (currently beneath the former crane tramway), likely at the same elevation vertically, but at an adjacent lateral location, so that the RA can be completed.

o To ensure construction access in the area around the former crane tramway and OF43, the RM11E Group will also have to coordinate remediation of the area with the remediation at the Glacier NW and Cargill docks. This approach may involve working in the area during the off-peak season at Glacier NW and/or Cargill.

Cargill Main Dock

Five remediation technology concepts are under consideration: diver dredging/dredging, ACB mat capping and dredging, remnant piling cap/dredging, AquaGate©/dredging, and bank layback and dredging (Figure 6-8)

Three potential approaches are identified for RA access:

o Start and stop the active remediation portion of the RA around the Irving Terminal during the typical in-water work window to allow terminal operations to continue uninterrupted (e.g., ships in and out), with associated


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multiple mobilization and demobilization efforts and extended time period for remedy completion.

o Temporarily shut down the Irving Terminal for the period needed to complete the active remediation portion of the RA around the Irving Terminal, with construction of replacement grain handling capacity at another Cargill facility to handle the temporary lost Irving Terminal capacity.

o Temporarily shut down the Irving Terminal for the period needed to demolish the Irving Terminal dock, complete the active remediation portion of the RA around the Irving Terminal, and reconstruct the dock, with construction of replacement grain handling capacity at another Cargill facility to handle the temporary lost Terminal Irving capacity.

8.2.3 Technical Studies for Alternatives Evaluation and RD Purpose: Technical studies will be used to identify the preferred alternative for the RM11E Project Area for 30% Design, including the preferred in-water work window.

The following evaluations, as described below, will be completed as part of an alternatives evaluation and the 30% Design, with detailed assessments completed as needed through 60% Design: geotechnical, structural, hydrodynamic, dredging, capping, in situ treatment, habitat, in-water work windows, and cost estimates. The details of studies and approaches will be presented in the RDWP.

A Preferred Alternative Report will summarize the findings of the studies for the alternatives evaluation and will present the preferred alternative for completing the 30% Design.

Geotechnical Purpose: Geotechnical assessments will establish engineering soil properties and will evaluate slope stability, slope stabilization, and piling capacity in support of the evaluation, selection, and design of remediation technologies.

Geotechnical studies—including subsurface explorations and testing41—will evaluate the current condition of the oversteepened slopes at the site, the potential impact of RAs on slope stability, and the development of design parameters to address slope stability where needed during and following RA, including criteria for RMC material on slopes. Geotechnical evaluations will also include seismic considerations as it pertains to cap design, maintenance, and repair following a seismic event. As needed, soil loading parameters will be developed to support structural stability and facility modification evaluations as well as for assessing implementability limitations regarding dredging setbacks from docks and in-water structures.

41 Geotechnical exploration will include chemical analysis of collected soil samples to aid in the delineation of RT materials at the site.


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Structural Purpose: Structural assessments will evaluate the potential effects of RAs on existing waterfront and offshore structures (e.g., silos, docks, dolphins), and develop preliminary concepts for facility modification options for improved access to Target Material during RA.

Evaluation of the potential for existing structures to be damaged due to changes in loading profiles resulting from proposed remediation technologies (both capping and dredging) will be performed in conjunction with geotechnical design studies as needed for selection of the preferred alternative. The assessment will identify dredging offsets from existing structures and will define parameters to protect functional piles and pile-supported structures, retaining walls (including the soldier pile and tieback walls at Cargill and the block wall at RIS&G), and adjacent upland buildings and structures from damage during or caused by remediation. Preliminary structural design will be provided for proposed retaining walls, alternative capping systems, incorporation of existing remnant piling into tiered retaining walls, and identified facility modifications for RA access.

Hydrodynamic Purpose: Hydrodynamic evaluations will establish design parameters for sizing of stable capping and armoring components against current and future erosion forces from river flows, eddy currents, wind-generated waves, vessel wakes, and propeller wash.

The design parameters will be used in the development of the 30% Design for the RM11E Project Area. During 30% Design a site-specific zero-flood-rise analysis may be completed for the preferred alternative.

Dredging Purpose: Dredging evaluations will support the alternatives evaluation and establish preliminary dredging plans for removal of Target Material for portions of the site where both dredging and capping are under consideration. Dredging evaluations will also establish dredging parameters for the 30% Design.

The 30% Design dredging will apply the RDMs as appropriate for different water depths and river regions, for working in open areas as well as under/behind docks, for sloping bed and level bed areas, for removal and management of debris, and for managing water quality during dredging. The 30% Design will also address dredged material handling, processing, transport, transload, and disposal along with placement of RMC following dredging.

Capping Purpose: Capping studies will identify and consider specific capping components including various granular materials and amendments, and hybrid systems, such as ACB mats, to chemically isolate Target Material in support of the alternatives analysis and for 30% Design.

The caps will be configured on the basis of site-specific conditions including erosion potential, slope stability, structure protection, constructability, thickness and chemical nature of material to be capped, porewater characteristics, and seepage rates. Caps will include armoring materials as needed to protect against erosion, and amendments such as PAC as needed to manage potential migration of porewater contaminants through the cap.


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In Situ Treatment Purpose: In situ treatment studies will address the constructability of placing AquaGate® or similar materials in areas of apparent thin Target Material, such as under and behind the Cargill Main dock for the alternatives evaluation and for 30% Design if selected. Pilot studies and/or bench tests, if needed, will be identified during 30% Design for implementation in a later design stage.

Habitat Purpose. Habitat evaluations will be completed for the 30% Design to identify changes in habitat from proposed RAs and establish the potential need for compensatory habitat mitigation to achieve substantive compliance with Section 404 of the CWA.

Habitat evaluations will include compilation of available data along with site surveys as needed to catalog existing side slopes, substrates, elevation zones, and vegetation. This information will be used in a Habitat Equivalency Analysis (HEA) model to describe a habitat baseline for the site. After the preferred alternative is identified for the RM11E Project Area, it will be input into a HEA as a basis for comparing pre- and post-remediation conditions, identifying compensatory habitat mitigation needs, if any, and in support of later preparation of an ESA biological assessment.

A more thorough technical investigation of the potential impacts of the RM11E remediation on special status species will be included in the Alternatives Evaluation including:

The potential impacts of an expanded work window on Pacific lamprey.

Information on the vertical distribution of salmonid species. The analysis will consider the effect of vertical distribution of fish on potential exposure.

Comparison of the sediment grain size at a remediation dredging project on the Duwamish River with those at RM 11 E to determine if the proposed dredging methods are expected to be as effective at RM 11 E as they were in the Duwamish.

Exposure in number of days in each of the specific RM11E work zones. This analysis can also consider the differences in exposure that can occur based on the level of COC contamination in that zone, including the potential for chemical mixtures to be an amplifying factor.

Potential impacts of exposure during remediation by all pathways and provide a context for comparing the relative effects of alternative remedial designs on a whole project basis. Once the preferred alternative is selected, a BA will be prepared that will include a detailed impact analysis for the Project.

More detailed information on the need to expand the in-water work window, and will include a comparison of the short-term adverse impacts of completing the work over fewer years as opposed to a longer remediation schedule with ongoing exposure to ESA species from baseline contamination.

A RM11E BA will be prepared addressing the selected alternative on all ESA listed species including, but not limited to, the species addressed in Appendix C, upper Willamette River


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steelhead, lower Columbia River steelhead and Lower Columbia River Coho salmon. The Alternatives Evaluation and BA will also:

Draw the distinction between yearling and subyearling Chinook salmon relative to their residence time in the LWR. Specifically, because subyearlings can spend a prolonged amount of time in Portland Harbor, they can be more susceptible to exposure to existing sediment contamination.

Assume that some small subyearling Chinook salmon are present in the LWR in January and February. Further, the analysis will consider how existing habitat quality may affect fish density within the RM11E work zones during construction.

In-Water Work Windows Purpose: Complete additional studies, in consultation with EPA, as needed to identify the preferred RM11E in-water work window as part of the alternatives evaluation.

Ongoing agency coordination, including further work timing analysis, will be completed as needed during RD to support the selection of the preferred in-water work window for the RM11E Project Area RAs.

Concept Cost and Schedule Comparisons Purpose: Provide relative cost comparisons and schedules for evaluation of alternatives and for the 30% Design.

Concept level, comparative cost assessments, and construction schedules will be prepared as needed to complete the alternatives evaluation and select the preferred alternative. A preliminary estimate of probable cost will then be developed for the preferred alternative in the 30% Design.

8.2.4 Preferred Alternative Report Information from the technical studies and the preferred approaches for facility-related issues will be evaluated to identify a constructible and cost-effective remediation technology concept and approach for RA access for the refined SMAs in each region of the RM11E Project Area. The technology concepts and approach for RA access from each area will be combined to form the preferred alternative for the RM 11E Project Area for the 30% Design. The results of this evaluation, including the preferred in-water work window and refined SMAs, will be submitted in the Preferred Alternative Report for EPA review and approval. The preferred alternative will then be detailed in 30% Design level site plans and cross sections showing specific areas of dredging, capping (including hybrid capping technologies), in situ treatment, bank stabilization, facility modifications, changes to habitat characteristics, a 30% Design level estimate of probable costs, and a 30% Design level schedule based on the selected in-water work window.

8.3 Additional RD Investigations Additional RD investigations, if needed, will be for the purpose of filling data gaps identified during RD. While not evident at this time, additional design efforts could include activities such as:


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Additional sediment and site characterization to finalize RD in specific capping or dredging areas.

Structural and geotechnical evaluations for refined remediation concepts.

Further evaluating dredging related activities including dredged material processing and water treatment and development of a project-specific sediment transload facility.

Pilot tests including evolving technologies for in situ treatment.

Evaluating habitat mitigation projects.

The scope of additional RD investigations would be implemented per EPA-approved work plans.


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9. Remedial Design Sequencing

RD starts with development of a RDWP, followed by the 30% Design and associated technical studies, then 60%, 95%, and 100% final design progress stages, as described below.

9.1 Remedial Design Work Plan The RDWP will define the scope and schedule for RD activities including an alternatives evaluation and associated technical studies, RD sediment characterization, 30-60-95-100% Design stages, and provisions for additional RD studies as identified. Specific technical studies proposed for the alternatives evaluation and 30% Design will be described in the RDWP for review and approval by EPA. A draft RDWP will be submitted to EPA 120 days after EPA’s approval of the Final BODR, with a Final RDWP submitted to EPA 30 days after receipt of EPA comments on the Draft RDWP.

9.2 30% Design The overall sequence of 30% Design is presented in Figure 9-1. Following approval of the RDWP, sediment sampling (Phase 1 RD Sediment Characterization) will begin in conjunction with the alternatives evaluation and associated technical studies. The Phase 1 sediment sampling results, including refined SMAs, and the results of the alternatives analysis, including identification of the preferred in-water work window, will be presented to EPA for review and approval in the Preferred Alternative Report. Phase 2 RD Sediment Sampling and 30% Design efforts will occur after EPA approval of the Preferred Alternative Report. The primary components of the 30% Design are as follows:

Sampling and Analysis. Sediment SAPs for RD Sediment Characterization (Section 8.1) will be submitted to EPA for review and approval. The Phase 1 SAP will be submitted with the RDWP. Sampling will occur in parallel with the alternatives evaluation and the results, including refined SMAs, will be included in the Preferred Alternative Report. The Phase 2 SAP will be submitted following EPA’s approval of the Preferred Alternative Report, with the sampling work occurring during the later stages of the 30% Design. Findings from the Phase 2 sampling will be submitted with the 30% Design report.

Alternatives Evaluation. The alternatives evaluation will begin upon approval of the final RDWP and will include technical studies described in Section 8.2.3 to identify the preferred alternative for the RM11E Project Area, including the preferred in-water work window. The results will be presented for EPA review and approval in the Preferred Alternative Report. After EPA’s approval of the Preferred Alternative Report, the preferred alternative will be used for completion of the 30% Design.

Preliminary (30%) Design Submittal. The 30% Design submittal will include the deliverables as stated in SOW:

a) Preliminary drawings and specifications


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b) Descriptions of permit requirements, if applicable

c) A description of how the RA will be implemented in a manner that minimizes environmental impacts in accordance with EPA’s Principles for Greener Cleanups (EPA, 2010)

d) Any proposed revisions to the RD Schedule that is set forth in Section 6.2 of the SOW (Schedule) and in the RDWP

e) All supporting deliverables required to accompany the Preliminary RD as specified in the RDWP

9.3 60% - 95% - 100% Design Three final stages of RD will refine the design of the preferred alternative as follows:

Intermediate (60%) Design. The Intermediate RD will be a continuation and expansion of the 30% Design; address EPA’s comments regarding the 30% Design; and include deliverables as stated in the SOW:

a) The same elements as are required for the Preliminary RD

b) Preliminary RA O&M Plan and O&M Manual

c) A description of RA monitoring and control measures to protect human health and the environment, such as air monitoring and dust suppression, during the RA

d) Emergency Response Plan (ERP). An ERP will be prepared to describe communication protocols and procedures to be used in the event of an accident or emergency at the RM11E Project Area during RA

e) Institutional Controls Implementation and Assurance Plan (ICIAP) for the RM11E Project Area

f) All supporting deliverables required to accompany the Intermediate RD as specified in the RDWP

Pre-Final (95%) Design. The Pre-Final RD will be a continuation and expansion of the Intermediate RD; and address EPA’s comments regarding the Intermediate RD. The Pre-Final RD will serve as the approved Final (100%) RD if EPA approves the Pre-Final RD without comments. The Pre-Final RD will include deliverables as stated in the SOW:

a) A complete set of construction drawings and specifications that: (1) are prepared to be certified by a registered professional engineer for the Final RD; (2) are suitable for procurement; and (3) follow the Construction Specifications Institute’s Master Format 2012

b) Survey and engineering drawings showing existing RM11E Project Area features, such as elements, property borders, easements, and RM11E Project Area conditions


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c) Pre-Final versions of the same elements and deliverables as are required for the Intermediate RD

d) A specification for photographic documentation of the RA

e) Supporting deliverables as specified in the RD Schedule and in the RDWP

Final (100%) Design. The Final RD will address EPA’s comments on the Pre-Final RD and include final versions of all Pre-Final deliverables.


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10. References

Amec Foster Wheeler, DOF, and Floyd|Snider. 2016. Corrective Measure Implementation Report, Duwamish Sediment Other Area and Southwest Bank Corrective Measure, Boeing Plant 2, Seattle/Tukwila, Washington. Submitted to The Boeing Company, Seattle, WA. Submitted by: Amec Foster Wheeler Environment & Infrastructure, Inc.; Dalton, Olmsted & Fuglevand, Inc. (DOF); Floyd Snider, Inc. June 2006.

Anchor QEA, LLC, Windward Environmental, LLC, Kennedy/Jenks Consultants, and Integral Consulting, Inc. 2012. Portland Harbor RI/FS Draft Feasibility Study, prepared for The Lower Willamette Group, March 30, 2012.

Anchor QEA. 2018. NW Natural’s Additional Revised Gasco Sediments Site Dredge and Cover Design, Implementation, Verification, and Closeout Approach. Memorandum to U.S. Environmental Protection Agency. Anchor QEA, LLC. December 14, 2018.

ASCE. 2014. American Society of Civil Engineers, 2014, ASCE 61-14, Seismic Design of Piers and Wharves, ASCE, Reston, Virginia.

ASCE. 2017. American Society of Civil Engineers, 2017, ASCE 7-16, Minimum Design Loads and Associated Criteria for Buildings and Other Structures, ASCE, Reston, Virginia.

Bauer, J. M., W.J. Burns, and I.P. Madin. 2018, Earthquake regional impact analysis for Clackamas, Multnomah, and Washington Counties, Oregon: Oregon Department of Geology and Mineral Industries Open-File Report 0-18-12.

Blakely, R. J., R.E. Wells, T.L. Tolan, M.H. Beeson, A.M. Trehu, and L.M. Liberty. 2000. New aeromagnetic data reveal large strike-slip faults in the northern Willamette Valley, Oregon: Geological Society of America Bulletin, v. 112, p. 1225–1233.

Bridges, T.S., S. Ells, D. Hayes, D. Mount, S. Nadeau, M. Palermo, C. Patmont, and P. Schroeder. 2008. The Four Rs of Environmental Dredging: Resuspension, Release, Residual, and Risk. Technical Report ERDC/EL TR-08-4. Vicksburg, MS: U.S. Army Engineer Waterways Experiment Station.

Cargill. 2014. Waterfront Facilities Activities Questionnaire response dated November 12, 2014.

Central Premix. 2012. Stormwater Pollution Prevention Plan. Oregon Department of Environmental Quality File No. 11133. March 19, 2012.

City of Portland. 2009. Non-Permittee Inspection of Facility at 1208 N River Street, City of Portland Bureau of Environmental Services Industrial Stormwater Program, June 11, 2009.

DEQ. 2016. Portland Harbor Upland Source Control Summary Report. Oregon Department of Environmental Quality, Northwest Region Cleanup Program. March 25, 2016.


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DOF and GSI. 2013. Supplemental Remedial Investigation / Feasibility Study Work Plan, River Mile 11 East, Portland OR, prepared for RM11E Group by Dalton, Olmsted & Fuglevand, Inc., and GSI Water Solutions, Inc., October.

DOF and GSI. 2018. Basis of Design Report Work Plan, Remedial Design, River Mile 11E, Portland, Oregon. Prepared for RM11E Group. May 2018.

DOF, DEA, KPFF, and Geotechnical Resources. 2015. Draft Implementability Study Report, Supplemental Remedial Investigation/Feasibility Study, River Mile 11 East, Portland, Oregon. Prepared for RM11E Group. Dalton, Olmstead & Fuglevand, Inc.; David Evans and Associates, Inc.; KPFF Consulting Engineers; and Geotechnical Resources, Inc. July 2015.

Ecology and Environment. 2018. Final Trip Report, Willamette Sediment Sampling Site, Portland, Oregon, TO-32. Prepared for U.S. EPA. August 2018.

EPA. 1995. Remedial Design/Remedial Action Handbook, EPA 540/R-95/059. U.S. Environmental Protection Agency (EPA). June 1995.

EPA. 2009. Principles for Greener Cleanups. U.S. Environmental Protection Agency. Office of Solid Waste and Emergency Response. August 27, 2009.

EPA. 2010. Superfund Green Remediation Strategy. Office of Solid Waste and Emergency Response. Office of Superfund Remediation and Technology Innovation. September.

EPA. 2016a. Portland Harbor RI/FS Final Remedial Investigation Report. CERCLA Docket No. 10-2001-0240. U.S. Environmental Protection Agency. September 28, 2001. Amended February 8, 2016.

EPA. 2016b. Portland Harbor RI/FS Feasibility Study Report. CERCLA Docket No. 10-2001-0240. U.S. Environmental Protection Agency and CDM Smith. September 28, 2001. Amended June 2016.

EPA. 2017. Record of Decision, Portland Harbor Superfund Site, Portland, Oregon. U.S. Environmental Protection Agency, Region 10. January 2017.

EPA. 2018a. Administrative Settlement Agreement and Order on Consent for Supplemental RI/FS Work and Remedial Design, Amendment No. 1. CERCLA Docket No. 10-2013-0087. U.S. Environmental Protection Agency, Region 10. January 11, 2018.

EPA. 2018b. Letter Re: RM11E Group Response to EPA Comments on the Draft Recontamination Assessment Report, River Mile 11 East Project Area, Portland, Oregon. Received by PacifiCorp. U.S. Environmental Protection Agency. October 22, 2018.

EPA. 2018c. Letter Re: Draft Recontamination Assessment Report, River Mile 11 East Project Area, Portland, Oregon. Received by PacifiCorp. U.S. Environmental Protection Agency. September 5, 2018.

EPA. 2018d. River Mile 11 East, Response to RM11E – Project Area and Sediment Management Areas Memorandum. Received by PacifiCorp. U.S. Environmental Protection Agency. January 26, 2018.


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EPA. 2018. “RM11E Project Area, Comments on the Final Trip Report for the Willamette Sediment Sampling Site, Stan Herman Warehouse Facility” Letter sent to RM11E Group on October 22, 2018.

EPA and DEQ. 2018. RM11E Sufficiency Assessment Summary. November 1, 2018.

ERM. 2013. Riverbank Soil Source Control Screening Evaluation, Portland Cement Terminal. Prepared for Glacier Northwest, Inc. ERM-West, Inc. May 2013.

ESTCP. 2017. Demonstration of In Situ Treatment with Reactive Amendments for Contaminated Sediments in Active DoD Harbors. ESTCP Project ER-201131. Department of Defense Environmental Security Technology Certification Program (ESTCP). January 2017.

FEMA. 2004. Federal Emergency Management Agency, 2004. Flood Insurance Rate Map Number 4101830091E, Map Revised October 19, 2004. Federal Emergency Management Agency, Washington, DC, https://msc.fema.gov/portal/home, accessed July 11, 2018.

FEMA. 2010. Federal Emergency Management Agency, 2010. Flood Insurance Study, City of Portland, Oregon, Multnomah, Clackamas, and Washington Counties, Federal Emergency Management Agency, Washington, DC, https://msc.fema.gov/portal/home, accessed July 11, 2018.

Francingues, N.R., and M.R. Palermo. 2005. Silt Curtains as a Dredging Project Management Practice. DOER Technical Notes Collection. ERDC-TN-DOER-E21. Vicksburg, MS: U.S. Army Engineering Research and Development Center.

Fuglevand, P.F. and R.S. Webb. 2012. Urban River Remediation Dredging Methods that Reduce Resuspension, Release, Residuals, and Risk. Proceedings, WEDA XXXII Technical Conference & TAMU 43 Dredging Seminar. San Antonio, Texas. June 10-13, 2012.

GSI. 2014. Final Supplemental Remedial Investigation/Feasibility Study Field Sampling and Data Report, River Mile 11 East, Portland, Oregon. Prepared for RM11E Group. GSI water Solutions, Inc. September 2014.

GSI. 2017. RM11E – Project Area and Sediment Management Areas. Technical Memo to RM11E Group. GSI Water Solutions, Inc. October 19, 2017.

GSI and DOF. 2013. Final Supplemental Remedial Investigation/Feasibility Study Work Plan, River Mile 11East. Prepared for RM11E Group by GSI Water Solutions, Inc. and Dalton, Olmsted & Fuglevand, Inc. (DOF). October 2013.

GSI and DOF. 2018. Final Recontamination Assessment Report, River Mile 11 East. Prepared for RM11E Group. November 2018.

Gustavson, K. and P. Schroeder. Review and Recommendations on Dredge Releases and Residuals Calculations from the Portland Harbor Draft Feasibility Study. Memo to Chip Humphrey and Kristine Koch, U.S. Environmental Protection Agency (EPA),


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Region 10, from Karl Gustavson and Paul Schroeder, US Army Engineer Research and Development Center (ERDC). May 24, 2013.

Herrera. 2015. Stormwater Assessment for Source Control Evaluation, ODOT Facility in Portland Harbor. Prepared for Oregon Department of Transportation. Herrera Environmental Consultants, Inc. September 22, 2015.

Integral. 2006. Portland Harbor RI/FS Round 3 January 2006 High-flow Surface Water Field Sampling Report. Prepared for the Lower Willamette Group. March 27, 2006.

Mabey, M., G.L. Black, I.P. Madin, D.B. Meier, T.L. Youd, C.F. Jones, and B. Rice. 1997. Relative earthquake hazard map of the Portland metro region, Clackamas, Multnomah, and Washington Counties, Oregon: Oregon Department of Geology and Mineral Industries IMS-1.

Madin, I.P. 1990. Earthquake-hazard geology maps of the Portland metropolitan area, Oregon; text and map explanation: Portland, OR, Oregon Department of Geology and Mineral Industries.

MFA and ECONW. 2016. Wastewater Treatment Plant Lagoon Repurposing Market Analysis. Prepared for City of St. Helens. Maul Foster & Alongi, Inc. July, 2016.

Northwest Regional Sediment Evaluation Team (RSET). 2016. Sediment Evaluation Framework for the Pacific Northwest. Prepared by the RSET Agencies, July 2016.

Personius, F. F., R.L. Dart, L., Bradley, and K.M. Haller. 2003. Map and Data for Quaternary Faults and Folds in Oregon, USGS Open-File Report 03-095.

Palermo, M.R., P.R. Schroeder, T.J. Estes, N.R. Francingues. 2008. Technical Guidelines for Environmental Dredging of Contaminated Sediments. ERDC/EL TR-08-29. Environmental Laboratory, U.S. Army Engineering Research Center, Vicksburg, MS. September 2008.

RM11E Group. 2018. “RM11E Project Area, Comments on the Final Trip Report for the Willamette Sediment Sampling Site, Stan Herman Warehouse Facility” Letter to EPA dated August 21, 2018.

RMJOC. 2018. Climate and Hydrology Datasets for RMJOC Long Term Planning Studies: Second Edition (RMJOC-II). Prepared by River Management Joint Operating Committee (RMJOC): Bonneville Power Administration, United States Army Corps of Engineers, United States Bureau of Reclamation June 2018.

SEE, DOF, and GSI. 2015. Final Porewater Characterization Report: River Mile 11 East, Willamette River, Portland Oregon. Prepared for RM11E Group. Science, Engineering, and the Environment, LLC (SEE); Dalton, Olmstead & Fuglevand, Inc. (DOF); and Groundwater Solutions, Inc. (GSI).

Swanson, R.D., W.D. McFarland, J.B. Gonthier, and J.M. Wilkinson. 1993. A Description of Hydrogeologic Units in the Portland Basin, Oregon, and Washington. U.S. Geological Survey, Washington, DC. Water Resources Investigations Report 909-4196.


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Unkeles, 2014. Waterfront Facilities Activities Questionnaire response dated October 14, 2014.

USGS. 2014. U. S. Geological Survey, 2014, Unified hazard tool, accessed June 19, 2018, from USGS website: https://earthquake.usgs.gov/hazards/interactive/

Tables

Basis of Design ReportRiver Mile 11 East

Page 1 of 36

Table 1-1RM11E Elevation-Related CriteriaJurisdictional Lines1 CRD (ft) NAVD88 (ft)USACE (OHW) +14.8 +20.1DEQ (MHW) +7.8 2 +13.1 2

FEMA (BFE) +32Project Lines CRD (ft) NAVD88 (ft)Top of Intermediate Area -2.0 3 +3.3 3

Top of Shallow Area +7.7 +13.0 4

Habitat Areas (NMFS) -15.0 5 -9.7 5

Authorized USACE Navigation Channel Depth -43.0 -37.7HEA Boundaries CRD (ft) NAVD88 (ft)Top of ACM6 +14.8 +20.1Top of Shallow Water +2.7 +8Top of Deep Water -12.3 -7.0

Notes:

ACM = Active Channel Margin

BFE = Base Flood Elevation

BODR = Basis of Design Report

CRD = Columbia River Datum

DEQ = Oregon Department of Environmental Quality

FEMA = Federal Emergency Management Agency

FS = feasibility study

ft = feet

HEA = habitat equivalency analysis

MHW = mean high water

NAVD88 = North American Vertical Datum of 1988

NMFS = National Marine Fisheries Service

NRDA = natural resource damage assessment

OHW = ordinary high water

PHSS = Portland Harbor Superfund Site

RM = River Mile

ROD = PHSS Record of Decision (EPA, 2017a)

USACE = U.S. Army Corps of Engineers

6 Oregon Department of Environmental Quality (DEQ), National Oceanic and Atmospheric Administration (NOAA), and U.S. Army Corps of Engineers (USACE). 2016. Permitting assistance tools for bankwork projects in or near Portland Harbor. Retrieved online. URL: https://www.nwp.usace.army.mil/Portals/24/docs/regulatory/apply/Portland_Harbor_Permitting_Guide.pdf. November 2016.

4 ROD does not define elevation of top of shallow area. BODR uses +13 ft NAVD88 as top of shallow area based on the PHSS Final FS.5 Habitat areas currently defined by NMFS as those above -15 ft CRD from ROD Section 14.2.9.1. For BODR round -9.7 ft NAVD88 to -10 ft NAVD88.

1 Values for RM 11; CRD OHW elevation is the same for RM 10, but conversion factors to NAVD88 differ slightly at RM 10.2 Calculated based on difference between USACE-established OHW at RM 2 and DEQ reference elevation for MHW at RM 2.5; not verified at RM 11.3 Top of Intermediate Area elevation at -2 ft CRD from ROD Section 14.2.3. For BODR round +3.3 ft NAVD88 to +3 ft NAVD88.


Page 2 of 36

Table 2-1Source Control Sufficiency Assessment Summary Matrix1

Site ECSI # Pathway (s) Status2 Sufficiency Assessment

Contaminants

Milestone Document Remedial Design/Source Control Task

PacifiCorp-Albina River lots 5117 NA A NA Source Control Decision, July 14, 2017

NA

PacifiCorp-Knott Substation 5117 NA A NA Source Control Decision, April 5, 2013

NA

Tarr Inc. 1139 GW B Chlorinated VOCs Record of Decision, July 17, 2017 DEQ ROD requires source area treatment and performance monitoring for groundwater path.

Glacier Northwest River Street Terminal (Glacier NW)

5549 SW B BEHP Source Control Measures Implementation Report, Nov 2016

Additional stormwater source control measures and performance monitoring for BEHP continues. Recent source tracing results presented in a September 2018 letter report available on ECSI. Source not yet fully controlled.

Westinghouse Property (Former) 4497 GW,SW A NA Source Control Decision, January 7, 2019

NA

Cargill-Irving Terminal (Cargill) 5561 SW B Metals Source Control Evaluation, July 2014

Stormwater controls are being evaluated through monitoring. Most recent sampling results presented in February 2018 stormwater sampling report available on ECSI.

Tucker Building 3036 NA A NA Source Control Decision, July 2017 NA

Valvoline Inc. 3215 NA A NA NA Excluded for SCE – no source or incomplete pathway.Master Chemical, Inc. 1302 NA A NA NA Excluded for SCE – no source or incomplete pathway.Ross Island Sand & Gravel 5577 RB B NA Source Control Evaluation Letter,

June 6, 2011DEQ/EPA to confirm riverbank erosion pathway not a concern. DEQ issued a site inspection request October 8, 2018.

Vermiculite Northwest, Inc. (Former; WR Grace) 2761 NA A NA NA Excluded for SCE – no source or incomplete pathway.

Cascade Brake Products 1019 NA A NA NA Excluded for SCE – no source or incomplete pathway.Campbell Dry Cleaner (Former) 5680 NA A NA NFA Determination July 2016 Excluded for SCE – no source or incomplete pathway.Kenton Foundry (Former) 5758 GW, SW A PCBs, metals ICP Report, April 2015. Source

Control Evaluation pendingSite is adjacent to Westinghouse, and as with that site has been subject to contaminant removal and redevelopment by City of Portland. Stormwater issues have been resolved, and groundwater data for Westinghouse are applicable to Kenton Foundry (no downgradient impacts). SCE and DEQ SCD pending.

UPRR Albina Yard 178 SW B NA -- SW discharge to the RM11E SMA from the UPRR Albina Yard is limited to a small parking area that drains to Outfall 45. Assigned low priority given the limited size and historical low concentrations. SCE work pending.

Riverstreet Warehouse Fire (Stan Herman Site) 6225 RB A NA EPA October 22, 2018 letter Riverbank and upland capped by rock following EPA emergency response. EPA and DEQ concur that riverbank does not pose a recontamination risk, while the limited site upland is either paved or capped by rock.

ODOT/Stan Herman/KFJacobson Lease

- RB C PAHs associated with asphalt

grindings

NA DEQ working with ODOT to remove/contain asphalt grindings in “ramp area” jointly owned by ODOT and Stan Herman, and with ODOT on leaseholder (KF Jacobson) management of asphaltic material on ODOT property beneath the Fremont Bridge.

2100 N. Albina (Albina Development Project) 6287 SW, GW B TPH, metals Phase 1 ESA; December 2017 PPA signed with DEQ, source control related investigation in progress. ODOT Fremont Bridge 5437 SW B Metals, PAHs,

BEHP, PCBs, DDx

NA Additional stormwater source control measures needed for Fremont Bridge scuppers and areas draining to outfall WR-306 and performance monitoring.

City of Portland 2425 SW A NA City of Portland Effectiveness Monitoring Report July 2018

Source control decision pending

Upriver - SD B PH COCs NA Site-wide baseline and long term monitoringIn-Water SMA - SD,PW,OW C PH Focused

COCsNA To be addressed during design


Page 3 of 36

Table 2-1Source Control Sufficiency Assessment Summary Matrix1

Notes1 This table reflects the updated RM11E Sufficiency Assessment Summary provided by EPA and DEQ to the RM11E Group on November 1, 2018.2 Site status is indicated as follows:Shading indicates sites for which source control decisions have been completed by DEQ

(A) Sources are sufficiently controlled

(B) Sources are conditionally controlled

(C) Sources are not sufficiently assessed or controlled

BEHP = Bis(2-ethylhexyl)phthalate

DDx = DDx is the sum of dichlorodiphenyltrichloroethane (DDT) and breakdown compounds dichlorodiphenyldichloroethane (DDD) and dichlorodiphenyldichloroethylene (DDE).

DEQ = Oregon Department of Environmental Quality

ECSI = Environmental Cleanup Site Information

ESA = Environmental Site Assessment

GW = Groundwater

NA = Not applicable, all pathway(s) excluded

ODOT = Oregon Department of Transportation

OW = Overwater activities

PAH = polycyclic aromatic hydrocarbons

PCB = polychlorinated biphenyl

PPA = Prospective Purchaser Agreement

PW = Porewater

RB = Riverbank erosion

ROD = Record of Decision

SCE = source control effectiveness

SD = Sediment

SW = Stormwater

VOC = volatile organic carbons


Page 4 of 36

Table 2-2Sediment and Soil Grain Size, Organic Carbon, and Total Solids Data

Sample ID Sample Date Upper Depth (cm)

Lower Depth (cm)

River Mile1 River Region2 Gravel (%) Sand (%) Silt (%) Clay (%) Total Fines

(%)

Surface Sediment SamplesLW2-G516 3-Sep-04 0 25 11 East Side 1.1 57.9 1.2 73.9 22.0 3.8 25.7

LW3-G771 6-Dec-07 0 23 10.9 Navigation Channel 1.14 62 2.6 63.9 21.7 3.0 24.7

LW3-G776 5-Dec-07 0 22 11.1 East Side 0.75 66.2 1.3 80.5 12.1 1.9 14.0

LW3-G777 5-Dec-07 0 21 11.2 Navigation Channel 0.17 84.1 57.0 44.1 1.1 0.5 1.7



LW3-GCA11E-C00 6-Dec-07 0 24 11.3 East Side 0.813 T 64 T 50.3 43.6 5.2 1.4 6.6

LW3-GCRSP11E 18-Oct-07 0 12 11.3 East Side 1.13 64.1 14.6 64.2 17.1 7.1 24.2

LW3-UG01 1-Feb-07 0 19 11.1 East Side 1.12 71.3 T 36.6 58.9 3.6 1.3 4.9

LW3-UG02 31-Jan-07 0 23 11.2 Navigation Channel 0.36 79.5 61.5 37.6 2.8 0.9 3.7

LW3-UG03 31-Jan-07 0 24 11.3 Navigation Channel 0.73 71.4 36.9 56.1 2.8 0.8 3.6

RM11E-C010-A (R2) 22-May-09 0 30 11.1 East Side 1.73 76.7 29.5 40.6 18.4 2.8 21.2

RM11E-G005 5-May-09 0 30 11.1 East Side 1.31 84.4 45.7 50.4 3.2 0.3 3.4


RM11E-G012 6-May-09 0 22 11.1 East Side 1.96 48.7 T 1.2 40.8 50.8 6.0 56.8

RM11E-G015 16-Jun-09 0 29 11.2 East Side 1.57 67.4 T 24.0 51.2 20.5 6.5 27.0

RM11E-G018 7-May-09 0 25 11.2 East Side 1.89 T 51 T 2.6 55.6 37.8 5.4 43.2

RM11E-G021 7-May-09 0 25 11.2 Navigation Channel 0.3 86 52.5 48.0 1.5 0.4 1.8


RM11E-G024 7-May-09 0 20 11.3 Navigation Channel 0.36 78.2 63.8 39.2 4.4 0.3 4.7


RM11E-G028 8-May-09 0 28 11.3 Navigation Channel 1.4 T 65.3 T 46.0 44.4 13.0 4.8 17.8



RM11E-G036 15-Jun-09 0 25 11.4 East Side 1.4 64.9 8.2 71.7 15.3 2.1 17.4

RM11E-G039 15-Jun-09 0 28 11.4 East Side 0.61 T 70.5 T 17.8 65.2 15.0 3.8 18.8

RM11E-G043 11-May-09 0 30 11.4 East Side 1.77 53.4 T 1.8 64.5 30.2 3.0 33.2

RM11E-G066 18-Jun-09 0 23 11.3 East Side 0.99 T 68.8 T 52.6 28.9 15.4 3.4 18.8

RM11E-G067 15-Jun-09 0 26 11.3 East Side 0.33 71 26.2 74.5 6.6 1.7 8.3

RM11E-G068 31-Oct-13 0 26 10.9 Navigation Channel 0.865 63.3 J 2.1 67.2 26.7 5.3 32.0

RM11E-G069 30-Oct-13 0 24 10.8 Navigation Channel 1.4 56.4 0.9 63.3 25.6 4.6 30.3


RM11E-G071 30-Oct-13 0 24 10.9 Navigation Channel 1.38 66 6.8 57.7 23.9 3.9 27.7

RM11E-G072 30-Oct-13 0 26 10.9 East Side 1.64 56.3 4.3 52.9 32.6 7.0 39.6





Total Organic Carbon

(%)

Black Carbon

(%)

Total Solids

(%)


Page 5 of 36



Lower Depth (cm)


(%)


(%)

Black Carbon

(%)

Total Solids

(%)


RM11E-G078 2-May-14 0 30.5 11.2 East Side 1 T 63.4 T 2.6 68.6 18.7 5.9 24.6


RM11E-G080 2-May-14 0 30.5 11.3 East Side 2.22 66.5 22.9 55.6 17.2 4.3 21.5

RM11E-G081 2-May-14 0 30.5 11.3 East Side 2.09 52 2.0 42.1 45.5 12.8 58.3







RM11E-G088 1-May-14 0 21.5 11.4 East Side 1.27 66.1 8.1 31.5 42.1 9.2 51.3


RM11E-PW001-SED 20-Oct-14 0 25.4 11.2 Navigation Channel 0.385 0.18 U 76.5 8.0 85.9 3.3 1.0 4.3

RM11E-PW002-SED 20-Oct-14 0 30.5 11.3 East Side 2.51 0.17 J 60.6 7.5 62.0 18.1 7.8 25.9

RM11E-PW003-SED 20-Oct-14 0 24.4 11.3 East Side 2.63 4.66 60.7 34.4 21.7 37.3 14.9 52.2

RM11E-PW004-SED 20-Oct-14 0 30.5 11.3 East Side 1.16 T 0.16 UT 74.4 T 18.3 78.1 4.0 1.6 5.6

RM11E-PW005-SED 20-Oct-14 0 30.5 11.3 Navigation Channel 0.954 0.18 U 70.5 49.8 42.4 10.2 5.3 15.5

RM11E-PW006-SED 20-Oct-14 0 30.5 11.4 East Side 0.924 0.18 U 66.5 0.0 43.8 44.4 12.2 56.6

WLCDRD05PG06363 23-May-05 0 24 10.9 East Side 1.47 56 0.7 72.5 25.2 4.1 29.3

Subsurface Sediment SamplesLW3-UC01-B 7-Feb-07 30 93 11.1 East Side 2.03 60.4 T 3.7 47.6 37.7 10.6 48.3

RM11E-C003-B 21-May-09 30.5 91.4 11.1 East Side 2.27 65.3 4.3 59.4 33.3 0.5 33.8

RM11E-C006-B 20-May-09 30.5 90 11.1 East Side 0.63 83.1 78.7 23.6 2.1 2.1 4.2

RM11E-C008-B 26-May-09 30.5 91.4 11.1 Navigation Channel 0.05 81.9 16.3 83.8 0.0 0.1 0.1


LW3-C777-B 9-Jan-08 30 122 11.2 Navigation Channel 0.03 J 79 17.9 86.3 0.2 0.2 0.4

LW3-C777-C 9-Jan-08 122 215 11.2 Navigation Channel 0.02 J 80.9 9.3 89.8 0.4 0.3 0.7

LW3-C777-D 9-Jan-08 215 252 11.2 Navigation Channel 0.02 U 85 40.0 63.6 0.3 0.2 0.5

LW3-UC02-B 7-Feb-07 30 90 11.2 Navigation Channel 0.11 79.6 9.8 90.3 0.7 0.3 1.0

LW3-UC02-C 7-Feb-07 90 216 11.2 Navigation Channel 0.16 86.9 49.5 53.4 1.1 0.3 1.4

RM11E-C012-B 20-May-09 30.5 91.4 11.2 East Side 1.82 66.5 T 5.6 61.8 29.9 0.6 30.5


RM11E-C048-C (R1) 24-Jun-09 91.4 134 11.2 East Side 2.15 T 76.7 T 49.4 23.3 25.5 8.5 34.0

WLCGWF03GNCOMP2003 6-Jun-03 0 57.91 11.2 East Side 0.837 74.3 10.7 68.2 13.9 6.2 20.1

LW3-C778-B 9-Jan-08 30 118 11.3 Navigation Channel 0.03 J 84.3 35.1 65.1 0.2 0.2 0.4

LW3-C778-C 9-Jan-08 118 241 11.3 Navigation Channel 0.04 J 89.2 32.8 68.1 0.7 0.3 0.9

LW3-C779-B 9-Jan-08 30 97 11.3 Navigation Channel 0.31 75 4.1 95.5 1.8 0.5 2.3

LW3-C779-C 9-Jan-08 97 154 11.3 Navigation Channel 1.43 77 31.5 65.7 1.0 0.2 1.2


Page 6 of 36



Lower Depth (cm)


(%)


(%)

Black Carbon

(%)

Total Solids

(%)

LW3-C779-E 9-Jan-08 212 293 11.3 Navigation Channel 0.19 80.3 26.0 64.2 7.9 1.2 9.1

LW3-UC03-B 8-Feb-07 30 120 11.3 Navigation Channel 0.77 69.4 T 0.9 86.5 12.4 4.1 16.4

LW3-UC03-C 8-Feb-07 120 242 11.3 Navigation Channel 1.88 62.3 2.0 33.0 54.5 17.9 72.4

LW3-UC03-D 8-Feb-07 242 308 11.3 Navigation Channel 1.69 63.9 1.0 36.7 52.9 12.3 65.2


RM11E-C019-D 21-May-09 152.4 213.4 11.3 East Side 2.1 T 59.1 T 0.0 41.8 47.9 15.3 63.2


RM11E-C022-C 20-May-09 91.4 140 11.3 East Side 1.91 61.6 4.4 40.2 41.3 14.1 55.4


RM11E-C023-E 21-May-09 213.4 301 11.3 East Side 1.29 63.9 5.0 74.2 23.1 5.6 28.7



RM11E-C026-E 22-May-09 213.4 304.8 11.3 East Side 0.66 66.1 T 1.1 50.6 41.8 9.3 51.1

RM11E-C026-F 22-May-09 304.8 381 11.3 East Side 0.02 U 77.9 T 0.0 94.1 3.4 0.7 4.1

RM11E-C047-B 23-Jun-09 30.5 91.4 11.3 East Side 0.76 73 43.5 35.8 23.8 0.4 24.2

RM11E-C029-B 23-Jun-09 30.5 91.4 11.4 East Side 0.84 T 64.1 T 0.3 40.4 52.2 10.7 62.9

RM11E-C032-B 23-Jun-09 30.5 91.4 11.4 East Side 1.06 59.3 4.4 29.3 62.1 10.7 72.8


RM11E-C035-C 21-May-09 91.4 152.4 11.4 East Side 0.96 66.5 0.0 49.3 41.4 9.6 51.0


RM11E-C038-B 20-May-09 30.5 91.4 11.4 East Side 0.18 80 T 6.4 87.9 4.5 1.1 5.6

Monitoring Well Soil Boring SamplesRM11E-MWS005-21_26' 22-Nov-13 640 792 11.1 East Side 1.85 72.3 4.9 47.9 36.3 10.3 46.6

RM11E-MWS005-5_21' 22-Nov-13 152 640 11.1 East Side 1.23 80.5 32.4 15.5 40.1 15.0 55.1


RM11E-MWS001-5_24' 21-Nov-13 152 732 11.3 East Side 0.76 83 45.1 23.0 25.2 9.3 34.5

RM11E-MWS002s-20_25' 20-Nov-13 610 762 11.3 East Side 0.692 69 38.1 21.1 25.8 11.1 37.0

RM11E-MWS002s-5_20' 20-Nov-13 152 610 11.3 East Side 0.879 78.8 43.1 29.4 21.5 1.5 23.0


Notes:

Definition of data qualifiers:U = The material was analyzed for, but was not detected. The associated numerical value is the method detection limit (MDL).

J = The associated numerical value is an estimated quantity.

T = The associated numerical value was mathematically derived (e.g., from summing multiple analyte results such as Aroclors, or calculating the average of multiple results for a single analyte).

2 River region indicates if the sample was collected within the federally authorized Navigation Channel or in the nearshore areas east of the Navigation Channel (i.e. "East Side").

1 River mile shown reports the nearest downstream tenth of river mile in the Willamette River, as measured upstream from the confluence with the Columbia River. Therefore the river mile shown represents a range, from the river mile tenth that is shown to the next upstream tenth. For example "RM 11.3" represents samples collected between RM 11.3 and 11.4.


Page 7 of 36

Table 2-3Visual Sediment and Soil Sample Observations

RI Surface Sediment SamplesRM11E-C010-A (R2) 22-May-09 0.0 30.0 11.1 East Side Gravel 15 Silty Sandy Gravel NDRM11E-C012-A 20-May-09 0.0 30.5 11.2 East Side Sand 10 Silty Sand Clayey Silt LowRM11E-C033-A 18-May-09 0.0 30.5 11.4 East Side Silt 4 Silt Silty Clay HighRM11E-G001 5-May-09 0.0 27.5 11 East Side Silt 5 Sandy Silt HighRM11E-G002 5-May-09 0.0 20.0 11 Nav Channel Sand 10 Silty Sand HighRM11E-G003 13-May-09 0.0 30.0 11.1 East Side Gravel 17 Gravel NDRM11E-G004 5-May-09 0.0 15.0 11.1 Nav Channel Silt 5 Sandy Silt NDRM11E-G005 5-May-09 0.0 30.0 11.1 East Side Sand 11 Sand Gravel NDRM11E-G006 5-May-09 0.0 12.0 11.1 East Side Sand 10 Silty Sand HighRM11E-G007 5-May-09 0.0 28.0 11.1 Nav Channel Sand 11 Sand NDRM11E-G008 6-May-09 0.0 17.0 11.1 East Side Silt 4 Silt Silty Clay HighRM11E-G009 6-May-09 0.0 17.0 11.1 East Side Sand 10 Silty Sand Sandy Silt HighRM11E-G010 6-May-09 0.0 20.0 11.1 Nav Channel Sand 11 Sand HighRM11E-G011 6-May-09 0.0 27.0 11.1 Nav Channel Sand 11 Sand LowRM11E-G012 6-May-09 0.0 22.0 11.1 East Side Silt 2 Clayey Silt Silty Clay NDRM11E-G013 15-Jun-09 0.0 17.0 11.1 East Side Gravel 16 Sandy Gravel HighRM11E-G014 6-May-09 0.0 22.0 11.1 Nav Channel Sand 13 Gravelly Sand LowRM11E-G015 16-Jun-09 0.0 29.0 11.2 East Side Silt 2 Clayey Silt NDRM11E-G016 7-May-09 0.0 28.0 11.2 East Side Gravel 16 Sandy Gravel NDRM11E-G017 7-May-09 0.0 26.0 11.2 Nav Channel Sand 11 Sand HighRM11E-G018 7-May-09 0.0 25.0 11.2 East Side Silt 5 Sandy Silt LowRM11E-G019 16-Jun-09 0.0 23.0 11.2 East Side Silt 2 Clayey Silt Sand HighRM11E-G020 7-May-09 0.0 27.0 11.2 Nav Channel Sand 11 Sand NDRM11E-G021 7-May-09 0.0 25.0 11.2 Nav Channel Sand 11 Sand HighRM11E-G022 7-May-09 0.0 21.0 11.3 East Side Silt 5 Sandy Silt HighRM11E-G023 7-May-09 0.0 17.0 11.3 East Side Sand 11 Sand HighRM11E-G024 7-May-09 0.0 20.0 11.3 Nav Channel Sand 10 Silty Sand Sand HighRM11E-G025 8-May-09 0.0 25.0 11.3 Nav Channel Clay 1 Silty Clay HighRM11E-G026 8-May-09 0.0 17.0 11.3 East Side Silt 2 Clayey Silt NDRM11E-G027 8-May-09 0.0 22.0 11.3 East Side Sand 10 Silty Sand LowRM11E-G028 8-May-09 0.0 28.0 11.3 Nav Channel Sand 10 Silty Sand NDRM11E-G029 12-May-09 0.0 19.0 11.3 East Side Sand 10 Silty Sand NDRM11E-G030 8-May-09 0.0 20.0 11.3 East Side Sand 11 Sand HighRM11E-G031 8-May-09 0.0 23.0 11.3 Nav Channel Silt 2 Clayey Silt Sandy Gravel NDRM11E-G032 8-May-09 0.0 20.0 11.3 Nav Channel Sand 13 Gravelly Sand HighRM11E-G033 13-May-09 0.0 25.0 11.4 East Side Sand 11 Sand HighRM11E-G035 8-May-09 0.0 26.0 11.3 Nav Channel Gravel 16 Sandy Gravel LowRM11E-G036 15-Jun-09 0.0 25.0 11.4 East Side Silt 5 Sandy Silt High

Visual Sediment and Soil Descriptions3

Predominant Grain Size4 Secondary Description7 Organic Content8Primary Description6Sort5Sample ID River Region2River Mile1Lower Depth

(cm)Upper Depth

(cm)Sample Date


Page 8 of 36




(cm)Upper Depth

(cm)Sample Date

RM11E-G037 13-May-09 0.0 28.0 11.4 Nav Channel Sand 10 Silty Sand Sandy Gravel LowRM11E-G038 11-May-09 0.0 26.0 11.4 Nav Channel Sand 11 Sand LowRM11E-G039 15-Jun-09 0.0 28.0 11.4 East Side Silt 5 Sandy Silt Gravel NDRM11E-G040 13-May-09 0.0 22.0 11.4 Nav Channel Gravel 16 Sandy Gravel LowRM11E-G043 11-May-09 0.0 30.0 11.4 East Side Silt 2 Clayey Silt Silty Sand HighRM11E-G063 15-Jun-09 0.0 26.0 11.2 Nav Channel Sand 10 Silty Sand NDRM11E-G064 15-Jun-09 0.0 15.0 11.4 East Side Gravel 16 Sandy Gravel HighRM11E-G065 18-Jun-09 0.0 28.0 11.2 East Side Silt 5 Sandy Silt HighRM11E-G066 18-Jun-09 0.0 23.0 11.3 East Side Silt 5 Sandy Silt HighRM11E-G067 15-Jun-09 0.0 26.0 11.3 East Side Sand 10 Silty Sand Sand LowRM11E-G068 31-Oct-13 0.0 26.0 10.9 Nav Channel Sand 10 Silty Sand LowRM11E-G069 30-Oct-13 0.0 24.0 10.8 Nav Channel Silt 4 Silt Clayey Silt LowRM11E-G070 30-Oct-13 0.0 8.0 10.9 Nav Channel Silt 2 Clayey Silt NDRM11E-G071 30-Oct-13 0.0 24.0 10.9 Nav Channel Silt 5 Sandy Silt LowRM11E-G072 30-Oct-13 0.0 26.0 10.9 East Side Silt 6 Sandy Gravelly Silt Sandy Silt HighRM11E-G073 30-Oct-13 0.0 22.0 10.9 East Side Gravel 17 Gravel NDRM11E-G074 30-Oct-13 0.0 26.0 10.9 Nav Channel Silt 4 Silt NDRM11E-G075 31-Oct-13 0.0 17.0 10.9 East Side Sand 10 Silty Sand LowRM11E-G076 31-Oct-13 0.0 25.0 11.1 East Side Sand 10 Silty Sand HighRM11E-G077 31-Oct-13 0.0 22.0 11.2 Nav Channel Sand 10 Silty Sand HighRM11E-G078 2-May-14 0.0 30.5 11.2 East Side Sand 10 Silty Sand Silt LowRM11E-G079 31-Oct-13 0.0 23.0 11.2 Nav Channel Sand 10 Silty Sand NDRM11E-G080 2-May-14 0.0 30.5 11.3 East Side Silt 5 Sandy Silt Silty Sand LowRM11E-G081 2-May-14 0.0 30.5 11.3 East Side Silt 4 Silt HighRM11E-G082 31-Oct-13 0.0 20.0 11.3 Nav Channel Sand 12 Silty Gravelly Sand Silty Sand NDRM11E-G083 1-May-14 0.0 24.0 11.4 East Side Silt 4 Silt HighRM11E-G084 1-May-14 0.0 20.0 11.4 East Side Silt 4 Silt Gravel LowRM11E-G085 2-May-14 0.0 8.0 11.4 East Side Gravel 17 Gravel HighRM11E-G086 2-May-14 0.0 8.0 11.4 East Side Gravel 17 Gravel LowRM11E-G087 2-May-14 0.0 26.0 11.1 East Side Sand 11 Sand HighRM11E-G088 1-May-14 0.0 21.5 11.4 East Side Silt 4 Silt LowRM11E-G089 1-May-14 0.0 24.0 11.4 East Side Silt 4 Silt LowRM11E-PW001-SED 20-Oct-14 0.0 25.4 11.2 Nav Channel Sand 11 Sand Sandy Gravel LowRM11E-PW002-SED 20-Oct-14 0.0 30.5 11.3 East Side Silt 5 Sandy Silt Silty clay HighRM11E-PW003-SED 20-Oct-14 0.0 24.4 11.3 East Side Clay 1 Silty Clay Gravel NDRM11E-PW004-SED 20-Oct-14 0.0 30.5 11.3 East Side Sand 13 Gravelly Sand LowRM11E-PW005-SED 20-Oct-14 0.0 30.5 11.4 Nav Channel Sand 13 Gravelly Sand Silty clay NDRM11E-PW006-SED 20-Oct-14 0.0 30.5 11.4 East Side Silt 4 Silt Low


Page 9 of 36




(cm)Upper Depth

(cm)Sample Date

RI Shoreline Surface Sediment SamplesRM11E-SL001 22-Sep-09 0.0 10.0 11.1 East Side Sand 10 Silty Sand LowRM11E-SL002 22-Sep-09 0.0 10.0 11.1 East Side Sand 13 Gravelly Sand LowRM11E-SL003 22-Sep-09 0.0 10.0 11.1 East Side Silt 2 Clayey Silt NDRM11E-SL004 22-Sep-09 0.0 15.0 11.2 East Side Silt 6 Sandy Gravelly Silt NDRM11E-SL005 22-Sep-09 0.0 9.0 11.2 East Side Sand 12 Silty Gravelly Sand LowRM11E-SL006 22-Sep-09 0.0 5.0 11.2 East Side Sand 12 Silty Gravelly Sand LowRM11E-SL007 22-Sep-09 0.0 12.0 11.3 East Side Sand 12 Silty Gravelly Sand LowRM11E-SL008 22-Sep-09 0.0 10.0 11.3 East Side Sand 11 Sand LowRM11E-SL009 22-Sep-09 0.0 20.0 11.3 East Side Silt 2 Clayey Silt LowRM11E-SL010 22-Sep-09 0.0 15.0 11.5 East Side Gravel 15 Silty Sandy Gravel LowRM11E-SL011 22-Sep-09 0.0 20.0 11.4 East Side Gravel 15 Silty Sandy Gravel LowRM11E-SL012 23-Sep-09 0.0 14.0 11.3 East Side Gravel 15 Silty Sandy Gravel LowRM11E-SL013 23-Sep-09 0.0 10.0 11.4 East Side Gravel 15 Silty Sandy Gravel HighRM11E-SL014 23-Sep-09 0.0 12.0 11.4 East Side Silt 7 Gravelly Silt HighRM11E-SL015 23-Sep-09 0.0 25.0 11.3 East Side Silt 4 Silt NDRM11E-SL016 23-Sep-09 0.0 25.0 11.3 East Side Sand 11 Sand NDRM11E-SL017 23-Sep-09 0.0 15.0 11.3 East Side Silt 7 Gravelly Silt NDRM11E-SL018 23-Sep-09 0.0 15.0 11.3 East Side Silt 5 Sandy Silt HighRM11E-SL019 23-Sep-09 0.0 20.0 11.4 East Side Silt 4 Silt Gravelly Sand HighRM11E-SL020 23-Sep-09 0.0 20.0 11.4 East Side Sand 13 Gravelly Sand HighRM11E-SL021 27-Oct-09 0.0 20.0 11.3 East Side Silt 7 Gravelly Silt HighRM11E-SL022 27-Oct-09 0.0 18.0 11.3 East Side Gravel 14 Silty Gravel HighRM11E-SL023 27-Oct-09 0.0 22.0 11.3 East Side Sand 10 Silty Sand LowRM11E-SL028 22-Nov-13 0.0 30.0 11.1 East Side Sand 10 Silty Sand HighRM11E-SL029 22-Nov-13 0.0 28.0 11.2 East Side Silt 4 Silt HighRM11E-SL030 22-Nov-13 0.0 30.0 11.2 East Side Sand 10 Silty Sand HighRM11E-SL031 22-Nov-13 0.0 23.0 11.3 East Side Sand 10 Silty Sand NDRM11E-SL032 18-Nov-13 0.0 27.0 11.3 East Side Silt 4 Silt LowRM11E-SL033 18-Nov-13 0.0 29.0 11.4 East Side Silt 3 Clayey Sandy Silt LowRM11E-SL034 18-Nov-13 0.0 29.0 11.4 East Side Silt 3 Clayey Sandy Silt LowRI Riverbank Surface Soil Samples (Collected in the Cove at RM 11.3)RM11E-SL035 31-Oct-13 0.0 20.0 11.3 East Side Sand 9 Clayey Silty Sand LowRM11E-SL036 31-Oct-13 0.0 30.0 11.3 East Side Silt 5 Sandy Silt NDRI Subsurface Sediment SamplesRM11E-C001-B 23-May-09 30.5 91.4 11.1 East Side Gravel 16 Sandy Gravel NDRM11E-C001-C 23-May-09 91.4 148.0 11.1 East Side Gravel 16 Sandy Gravel NDRM11E-C002-B 23-May-09 30.5 91.4 11.1 Nav Channel Gravel 16 Sandy Gravel NDRM11E-C002-C 23-May-09 91.4 152.4 11.1 Nav Channel Gravel 16 Sandy Gravel ND


Page 10 of 36




(cm)Upper Depth

(cm)Sample Date

RM11E-C002-D 23-May-09 152.4 166.0 11.1 Nav Channel Gravel 16 Sandy Gravel Gravelly Sand NDRM11E-C003-B 21-May-09 30.5 91.4 11.1 East Side Sand 10 Silty Sand Clayey Silt HighRM11E-C003-C 21-May-09 91.4 152.4 11.1 East Side Gravel 17 Gravel NDRM11E-C003-D 21-May-09 152.4 172.0 11.1 East Side Silt 3 Clayey Sandy Silt NDRM11E-C004-B 26-May-09 30.5 91.4 11.1 East Side Gravel 14 Silty Gravel Sandy Gravel NDRM11E-C004-C 26-May-09 91.4 131.0 11.1 East Side Gravel 16 Sandy Gravel NDRM11E-C005-B 26-May-09 30.5 91.4 11.1 Nav Channel Sand 11 Sand Sandy Gravel NDRM11E-C005-C 26-May-09 91.4 152.4 11.1 Nav Channel Gravel 16 Sandy Gravel NDRM11E-C005-D 26-May-09 152.4 213.4 11.1 Nav Channel Sand 13 Gravelly Sand NDRM11E-C006-B 20-May-09 30.5 90.0 11.1 East Side Gravel 17 Gravel NDRM11E-C007-B 26-May-09 30.5 91.4 11.1 East Side Gravel 16 Sandy Gravel LowRM11E-C007-C 26-May-09 91.4 152.4 11.1 East Side Gravel 14 Silty Gravel Sandy Gravel NDRM11E-C007-D 26-May-09 152.4 213.4 11.1 East Side Gravel 14 Silty Gravel NDRM11E-C008-B 26-May-09 30.5 91.4 11.1 Nav Channel Sand 11 Sand Sandy Gravel NDRM11E-C008-C 26-May-09 91.4 152.4 11.1 Nav Channel Sand 13 Gravelly Sand Sandy Gravel NDRM11E-C008-D 26-May-09 152.4 213.4 11.1 Nav Channel Sand 13 Gravelly Sand LowRM11E-C009-B 21-May-09 30.5 91.4 11.1 East Side Silt 4 Silt Silty Clay HighRM11E-C009-C 21-May-09 91.4 128.0 11.1 East Side Gravel 17 Gravel NDRM11E-C010-B 22-May-09 30.5 91.4 11.1 East Side Gravel 16 Sandy Gravel Silty Sand HighRM11E-C010-C 22-May-09 91.4 152.4 11.1 East Side Sand 8 Clayey Sand NDRM11E-C010-D 22-May-09 152.4 169.0 11.1 East Side Gravel 16 Sandy Gravel NDRM11E-C011-B 27-May-09 30.5 91.4 11.1 Nav Channel Sand 11 Sand LowRM11E-C011-C 27-May-09 91.4 152.4 11.1 Nav Channel Sand 13 Gravelly Sand Sandy Gravel NDRM11E-C011-D 27-May-09 152.4 213.4 11.1 Nav Channel Gravel 16 Sandy Gravel NDRM11E-C012-B 20-May-09 30.5 91.4 11.2 East Side Silt 2 Clayey Silt HighRM11E-C012-C 20-May-09 91.4 152.4 11.2 East Side Gravel 16 Sandy Gravel NDRM11E-C012-D 20-May-09 152.4 213.4 11.2 East Side Sand 11 Sand NDRM11E-C012-E 20-May-09 213.0 274.0 11.2 East Side Sand 11 Sand NDRM11E-C013-B 22-May-09 30.5 91.4 11.2 East Side Gravel 16 Sandy Gravel HighRM11E-C013-C 22-May-09 91.4 152.4 11.2 East Side Gravel 16 Sandy Gravel HighRM11E-C013-D 22-May-09 152.4 217.0 11.2 East Side Gravel 16 Sandy Gravel HighRM11E-C014-B 23-May-09 30.5 91.4 11.2 Nav Channel Sand 11 Sand NDRM11E-C014-C 23-May-09 91.4 152.4 11.2 Nav Channel Gravel 16 Sandy Gravel NDRM11E-C014-D 23-May-09 152.4 201.0 11.2 Nav Channel Sand 13 Gravelly Sand NDRM11E-C015-B 21-May-09 30.5 91.4 11.2 East Side Silt 2 Clayey Silt Silty Sand NDRM11E-C015-C 21-May-09 91.4 152.4 11.2 East Side Silt 2 Clayey Silt Sandy Clay NDRM11E-C015-D 21-May-09 152.4 225.0 11.2 East Side Gravel 17 Gravel Sandy Clay NDRM11E-C016-B 22-May-09 30.5 91.4 11.2 East Side Gravel 16 Sandy Gravel NDRM11E-C016-C 22-May-09 91.4 152.4 11.2 East Side Sand 11 Sand Sandy Gravel High


Page 11 of 36




(cm)Upper Depth

(cm)Sample Date

RM11E-C016-D 22-May-09 152.4 173.0 11.2 East Side Sand 13 Gravelly Sand Sand LowRM11E-C017-B 23-May-09 30.5 91.4 11.2 Nav Channel Sand 13 Gravelly Sand Sand HighRM11E-C017-C 23-May-09 91.4 152.4 11.2 Nav Channel Sand 13 Gravelly Sand Sand NDRM11E-C017-D 23-May-09 152.4 213.4 11.2 Nav Channel Sand 11 Sand NDRM11E-C018-B 23-May-09 30.5 91.4 11.2 Nav Channel Gravel 16 Sandy Gravel NDRM11E-C018-C 23-May-09 91.4 152.0 11.2 Nav Channel Sand 13 Gravelly Sand Sandy Gravel NDRM11E-C019-B 21-May-09 30.5 91.4 11.3 East Side Silt 2 Clayey Silt Sand HighRM11E-C019-C 21-May-09 91.4 152.4 11.3 East Side Silt 2 Clayey Silt Sand HighRM11E-C019-D 21-May-09 152.4 213.4 11.3 East Side Silt 2 Clayey Silt Sand LowRM11E-C019-E 21-May-09 213.0 301.0 11.3 East Side Silt 2 Clayey Silt Silty Clay HighRM11E-C020-B 22-May-09 30.5 91.4 11.3 East Side Gravel 16 Sandy Gravel Sandy Silt LowRM11E-C020-C 22-May-09 91.4 141.0 11.3 East Side Gravel 16 Sandy Gravel Clayey Sandy Gravel HighRM11E-C021-B 19-May-09 30.5 91.4 11.3 Nav Channel Gravel 16 Sandy Gravel LowRM11E-C021-C 19-May-09 91.4 152.4 11.3 Nav Channel Sand 13 Gravelly Sand Sandy Gravel NDRM11E-C021-D 19-May-09 152.4 189.0 11.3 Nav Channel Sand 13 Gravelly Sand NDRM11E-C022-B 20-May-09 30.5 91.4 11.3 East Side Clay 1 Silty Clay Sandy Gravel NDRM11E-C022-C 20-May-09 91.4 140.0 11.3 East Side Clay 1 Silty Clay NDRM11E-C023-B 21-May-09 30.5 91.4 11.3 East Side Sand 10 Silty Sand LowRM11E-C023-C 21-May-09 91.4 152.4 11.3 East Side Silt 2 Clayey Silt Sand NDRM11E-C023-D 21-May-09 152.4 213.4 11.3 East Side Silt 2 Clayey Silt Sand NDRM11E-C023-E 21-May-09 213.4 301.0 11.3 East Side Silt 2 Clayey Silt Gravelly Sand NDRM11E-C024-B 27-May-09 30.5 91.4 11.3 Nav Channel Sand 11 Sand NDRM11E-C024-C 27-May-09 91.4 152.4 11.3 Nav Channel Sand 11 Sand NDRM11E-C024-D 27-May-09 152.4 213.4 11.3 Nav Channel Gravel 16 Sandy Gravel Sand NDRM11E-C025-B 22-May-09 30.5 91.4 11.3 East Side Sand 10 Silty Sand Sandy Gravel LowRM11E-C025-C 22-May-09 91.4 152.4 11.3 East Side Sand 10 Silty Sand LowRM11E-C025-D 22-May-09 152.4 194.0 11.3 East Side Sand 10 Silty Sand LowRM11E-C026-B 22-May-09 30.5 91.4 11.3 East Side Sand 11 Sand HighRM11E-C026-C 22-May-09 91.4 152.4 11.3 East Side Sand 11 Sand Silty Clay NDRM11E-C026-D 22-May-09 152.4 213.4 11.3 East Side Clay 1 Silty Clay LowRM11E-C026-E 22-May-09 213.4 304.8 11.3 East Side Clay 1 Silty Clay LowRM11E-C026-F 22-May-09 304.8 381.0 11.3 East Side Sand 11 Sand NDRM11E-C027-B 26-May-09 30.5 91.4 11.3 Nav Channel Sand 11 Sand HighRM11E-C027-C 26-May-09 91.4 152.4 11.3 Nav Channel Sand 13 Gravelly Sand Sand LowRM11E-C027-D 26-May-09 152.4 213.4 11.3 Nav Channel Gravel 16 Sandy Gravel NDRM11E-C028-B 26-May-09 30.5 91.4 11.3 Nav Channel Sand 11 Sand Sandy Gravel LowRM11E-C028-C 26-May-09 91.4 152.4 11.3 Nav Channel Gravel 16 Sandy Gravel NDRM11E-C028-D 26-May-09 152.4 198.0 11.3 Nav Channel Gravel 16 Sandy Gravel NDRM11E-C029-B 23-Jun-09 30.5 91.4 11.4 East Side Silt 5 Sandy Silt Low


Page 12 of 36




(cm)Upper Depth

(cm)Sample Date

RM11E-C029-C 23-Jun-09 91.4 152.4 11.4 East Side Silt 5 Sandy Silt Silt LowRM11E-C029-D 23-Jun-09 152.4 213.4 11.4 East Side Silt 2 Clayey Silt Silt LowRM11E-C029-E 23-Jun-09 213.4 304.8 11.4 East Side Silt 2 Clayey Silt Silt HighRM11E-C029-F 23-Jun-09 304.8 396.2 11.4 East Side Silt 4 Silt Sandy Silt HighRM11E-C029-G 23-Jun-09 396.2 436.0 11.4 East Side Silt 2 Clayey Silt NDRM11E-C031-B 23-May-09 30.5 91.4 11.3 Nav Channel Gravel 16 Sandy Gravel NDRM11E-C031-C 23-May-09 91.4 152.4 11.3 Nav Channel Gravel 16 Sandy Gravel NDRM11E-C031-D 23-May-09 152.4 217.0 11.3 Nav Channel Gravel 16 Sandy Gravel NDRM11E-C032-B 23-Jun-09 30.5 91.4 11.4 East Side Silt 5 Sandy Silt LowRM11E-C032-C 23-Jun-09 91.4 152.4 11.4 East Side Silt 5 Sandy Silt Silt LowRM11E-C032-D 23-Jun-09 152.4 213.4 11.4 East Side Silt 5 Sandy Silt Silt LowRM11E-C032-E 23-Jun-09 213.4 304.8 11.4 East Side Silt 2 Clayey Silt Sandy Silt LowRM11E-C032-F 23-Jun-09 304.8 341.0 11.4 East Side Silt 2 Clayey Silt Sandy Silt LowRM11E-C033-B 18-May-09 30.5 91.4 11.4 East Side Sand 11 Sand LowRM11E-C033-C 18-May-09 91.4 152.4 11.4 East Side Silt 2 Clayey Silt Sand LowRM11E-C033-D 18-May-09 152.4 213.4 11.4 East Side Silt 2 Clayey Silt Sand LowRM11E-C034-B 20-May-09 30.5 91.4 11.4 Nav Channel Gravel 16 Sandy Gravel Sand LowRM11E-C034-C 20-May-09 91.4 157.0 11.4 Nav Channel Gravel 16 Sandy Gravel Gravelly Sand NDRM11E-C035-B 21-May-09 30.5 91.4 11.4 East Side Sand 11 Sand LowRM11E-C035-C 21-May-09 91.4 152.4 11.4 East Side Clay 1 Silty Clay LowRM11E-C035-D 21-May-09 152.4 180.0 11.4 East Side Clay 1 Silty Clay LowRM11E-C036-B 20-May-09 30.5 91.4 11.4 Nav Channel Gravel 16 Sandy Gravel Sand LowRM11E-C036-C 20-May-09 91.4 152.4 11.4 Nav Channel Gravel 16 Sandy Gravel LowRM11E-C036-D 20-May-09 152.4 213.4 11.4 Nav Channel Sand 11 Sand Clayey Silt LowRM11E-C038-C 20-May-09 91.4 152.4 11.4 East Side Silt 2 Clayey Silt Sand LowRM11E-C038-D 20-May-09 152.4 213.4 11.4 East Side Silt 2 Clayey Silt HighRM11E-C047-B 23-Jun-09 30.5 91.4 11.3 East Side Gravel 16 Sandy Gravel Clayey Silt LowRM11E-C047-C 23-Jun-09 91.4 152.4 11.3 East Side Silt 2 Clayey Silt LowRM11E-C047-D 23-Jun-09 152.4 213.4 11.3 East Side Silt 2 Clayey Silt HighRM11E-C047-E 23-Jun-09 213.4 304.8 11.3 East Side Silt 2 Clayey Silt LowRM11E-C047-F 23-Jun-09 304.8 355.0 11.3 East Side Silt 2 Clayey Silt LowRM11E-C048-B (R1) 24-Jun-09 30.5 91.4 11.2 East Side Sand 10 Silty Sand Clayey Silt LowRM11E-C048-B (R2) 24-Jun-09 30.5 82.0 11.2 East Side Gravel 15 Silty Sandy Gravel Silty Sand LowRM11E-C048-C (R1) 24-Jun-09 91.4 134.0 11.2 East Side Silt 2 Clayey Silt LowRM11E-SL015-90-120 23-Sep-09 90.0 120.0 11.3 East Side Sand 11 Sand LowRI Monitoring Well Soil Boring SamplesRM11E-MWS001-24_29' 21-Nov-13 732.0 884.0 11.3 East Side Sand 8 Clayey Sand HighRM11E-MWS001-5_24' 21-Nov-13 152.0 732.0 11.3 East Side Sand 13 Gravelly Sand Clayey Silt LowRM11E-MWS002s-20_25' 20-Nov-13 610.0 762.0 11.3 East Side Silt 4 Silt High


Page 13 of 36




(cm)Upper Depth

(cm)Sample Date

RM11E-MWS002s-5_20' 20-Nov-13 152.0 610.0 11.3 East Side Silt 5 Sandy Silt Gravelly Silt LowRM11E-MWS004-24_29' 22-Nov-13 732.0 884.0 11.4 East Side Silt 4 Silt LowRM11E-MWS004-5_24' 22-Nov-13 152.0 732.0 11.4 East Side Silt 4 Silt HighRM11E-MWS005-21_26' 22-Nov-13 640.0 792.0 11.1 East Side Sand 11 Sand Clayey Silt LowRM11E-MWS005-5_21' 22-Nov-13 152.0 640.0 11.1 East Side Silt 2 Clayey Silt Low

Notes:

3 To augment the empirical grain-size results performed on only a subset of samples, the visual sediment and soil description logs were reviewed in order to assign lithologic descriptions to these RI samples.4 A simplified determination of the predominant grain-size within each sample interval was assigned.5 This number is assigned to the primary descriptions from finest (1) to coarsest (17) sediment type, so that simplified abbreviations can be used on the remedial technology cross-sections in Section 5.1.6 To expand the predominant grain-size assignment, a description of the predominant sediment type (e.g. silty sand) was developed for each sample interval.7 If the predominant sediment type varied across a sample interval and more than 25% of that interval was unique, then a secondary sediment type description was assigned.8 The relative amount of organics was noted as ranging from ND (not detected), to low, to high.




Page 14 of 36

Table 2-4Geotechnical Parameters in Surface and Subsurface Sediment Samples

SampleID Sample DateUpper Depth (cm)

Lower Depth (cm)

River Mile1 River Region2 Specific

Gravity

Bulk Density (g/cm3)

Gravimetric Water

Content (%)

Liquid Limit (%)

Plastic Limit (%)

Plasticity Index (%)

D 854 E 1109 E 160.3M D 4318 D 4318 D 4318

RM11E-G012 6-May-09 0 22 11.1 East Side 1.96 48.7 T 1.98 1.32 103 42.2 37.6 4.6

RM11E-G021 7-May-09 0 25 11.2 Navigation Channel 0.3 86 2.1 1.8 16.3 Non-Plastic Non-Plastic Non-Plastic

RM11E-G026 8-May-09 0 17 11.3 East Side 1.35 56.5 1.79 1.53 77.1 41.8 32 9.8

RM11E-G028 8-May-09 0 28 11.3 Navigation Channel 1.4 T 65.3 T 1.66 T 1.7 52.6 41.6 33.3 8.3

RM11E-G033 13-May-09 0 25 11.4 East Side 0.46 67.1 1.87 1.8 49 Non-Plastic Non-Plastic Non-Plastic

RM11E-C008-B 26-May-09 30.5 91.4 11.1 Navigation Channel 0.05 81.9 2.89 1.6 21.1 Non-Plastic Non-Plastic Non-Plastic

RM11E-C012-B 20-May-09 30.5 91.4 11.2 East Side 1.82 66.5 T 2.67 1.64 49.5 Non-Plastic Non-Plastic Non-Plastic

RM11E-C019-B 21-May-09 30.5 91.4 11.3 East Side 1.92 57.8 T 1.7 1.57 73.1 54.1 37.3 16.9

RM11E-C023-B 21-May-09 30.5 91.4 11.3 East Side 0.86 74.8 2 1.55 33.7 Non-Plastic Non-Plastic Non-Plastic

RM11E-C026-E 22-May-09 213.4 304.8 11.3 East Side 0.66 66.1 T 1.95 1.74 52.8 31 26.8 4.2

RM11E-C026-F 22-May-09 304.8 381 11.3 East Side 0.02 U 77.9 T 2.43 1.21 26.3 Non-Plastic Non-Plastic Non-Plastic

RM11E-C035-B 21-May-09 30.5 91.4 11.4 East Side 0.41 75.2 2.13 1.42 33 Non-Plastic Non-Plastic Non-Plastic

RM11E-C036-B 20-May-09 30.5 91.4 11.4 Navigation Channel 0.21 87.7 2.41 1.69 14 Non-Plastic Non-Plastic Non-Plastic

Notes:ASTM = American Standard for Testing Materials

4 While the majority of total solids samples were analyzed using ASTM Method E160.3M, some samples were also analyzed using PSEP procedures.



3 While the majority of total organic carbon (TOC) samples were analyzed using the Puget Sound Estuary Program (PSEP) protocols, some samples were also analyzed by the following ASTM Methods: E415.1, SW9060, D4129, SM5310C.


Surface Sediment Samples

Subsurface Sediment Samples

Total Organic

Carbon (%)

Total Solids (%)

PSEP 3 E160.3M 4ASTM Method



Page 15 of 36

Table 2-5Remediation Thresholds (RTs)

Focused Contaminant of Concern (COC) Units Threshold

ConcentrationApplicable RT

CriteriaThreshold

ConcentrationApplicable RT

Criteria1

Total PCBs ug/kg 75Nearshore

RAL200

PTW Threshold

Total PAHs ug/kg 30,0002 Nearshore RAL

170,000Navigation

Channel RAL

Total DDx ug/kg 160Nearshore

RAL650

Navigation Channel RAL

PeCDD ug/kg 0.0008Nearshore

RAL0.003


PeCDF ug/kg 0.2Nearshore

RAL0.2

PTW Threshold

TCDD ug/kg 0.0006Nearshore

RAL0.002


Notes:

PAHs = polycyclic aromatic hydrocarbons

PCBs = polychlorinated biphenyls

PeCDD = 1,2,3,7,8-Pentachlorodibenzo-p-dioxin

PeCDF = 2,3,4,7,8-Pentachlorodibenzofuran

PTW = Principal Threat Waste

RAL = Remedial Action Level

TCDD = 2,3,7,8-Tetrachlorodibenzo-p-dioxin

Navigation Channel Nearshore Area

DDx = dichlorodiphenyltrichloroethane (DDT) and breakdown compounds dichlorodiphenyldichloroethane (DDD) and dichlorodiphenyldichloroethylene (DDE).

1 The Remediation Threshold (RT) in the navigation channel reflect the lower concentration of the "PTW Threshold" and "Navigation Channel RAL" values provided in Table 21 of the ROD.

2 EPA issued a proposed Explanation of Significant Differences (ESD) for the Portland Harbor Superfund Site (PHSS) in October 2018 (EPA, 2018). As part of the ESD, the Nearshore RAL for Total PAHs is proposed to increase from 13,000 ug/kg to 30,000 ug/kg. This modified RAL has not been finalized, however, in anticipation of its adoption, this modified RAL has been incorporated into this BODR.


Page 16 of 36

Table 2-6Focused COC Concentrations in Surface Sediment and Soil

Sample ID Sample Date

Upper Depth (cm)

Lower Depth (cm)

River Mile1 River Region2 Total PCBs3 Total PAH4 Total DDx5 PeCDD6 PeCDF7 TCDD8 Any RT

Exceedances?9

75 13000 160 0.0008 0.2 0.0006 --

200 - 7050 0.01 0.2 0.01 --

1000 170000 650 0.003 1 0.002 --

9 23000 6.1 0.0002 0.0003 0.0002 --

LW2-G516 3-Sep-04 0 25 11 East Side 32 JT 2300 T 9 JT -- -- -- NoLW3-G771 6-Dec-07 0 23 10.9 Nav Channel 95 NJT 550 T 12 NJT -- -- -- NoLW3-G776 5-Dec-07 0 22 11.1 East Side 2700 JT 360 T 60 NJT -- -- -- YesLW3-G777 5-Dec-07 0 21 11.2 Nav Channel 57 JT 64 JT 0.78 T -- -- -- NoLW3-G778 5-Dec-07 0 22 11.3 Nav Channel 580 T 700 JT 150 T -- -- -- YesLW3-G779 5-Dec-07 0 23 11.3 Nav Channel 200 JT 30 JT 17 NJT -- -- -- YesLW3-GCA11E-C00 6-Dec-07 0 24 11.3 East Side 6600 JT 410 JT 460 JT 0.000219 J 0.00043 U 0.0000981 U YesLW3-GCRSP11E 18-Oct-07 0 12 11.3 East Side 11 JT 810 JT 69 NJT 0.000451 J 0.000618 J 0.00014 U NoLW3-UG01 1-Feb-07 0 19 11.1 East Side 320 NJT 980 AJT 18 JT -- -- -- YesLW3-UG02 31-Jan-07 0 23 11.2 Nav Channel 6000 JT 110 JT 260 T -- -- -- YesLW3-UG03 31-Jan-07 0 24 11.3 Nav Channel 1200 JT 950 AJT 26 NJT -- -- -- YesRM11E-C010-A (R2) 22-May-09 0 30 11.1 East Side 100 T 1600 T 3.6 T 0.00038 J 0.000323 J 0.000103 J YesRM11E-C012-A 20-May-09 0 30.5 11.2 East Side 98 JT -- -- -- -- -- YesRM11E-C033-A 18-May-09 0 30.5 11.4 East Side 290 T -- -- -- -- -- YesRM11E-G001 5-May-09 0 27.5 11 East Side 72 JT -- -- -- -- -- NoRM11E-G002 5-May-09 0 20 11 Nav Channel 21 JT -- -- -- -- -- NoRM11E-G003 13-May-09 0 30 11.1 East Side 8.1 JT -- 0.52 T -- -- -- NoRM11E-G004 5-May-09 0 15 11.1 Nav Channel 9.8 JT -- NoRM11E-G005 5-May-09 0 30 11.1 East Side 20 JT 870 JT 2.4 JT 0.000642 J 0.000327 J 0.000119 J NoRM11E-G006 5-May-09 0 12 11.1 East Side 230 JT -- -- -- -- -- YesRM11E-G007 5-May-09 0 28 11.1 Nav Channel 1 UT -- -- -- -- -- NoRM11E-G008 6-May-09 0 17 11.1 East Side 35 JT 1800 T 2.3 JT 0.0015 J 0.000179 U 0.000423 U YesRM11E-G009 6-May-09 0 17 11.1 East Side 2900 JT -- -- -- -- -- YesRM11E-G010 6-May-09 0 20 11.1 Nav Channel 10 JT -- -- -- -- -- NoRM11E-G011 6-May-09 0 27 11.1 Nav Channel 13 JT -- -- -- -- -- NoRM11E-G012 6-May-09 0 22 11.1 East Side 16 JT 190 JT 2.5 JT 0.000194 U 0.000104 U 0.000196 U NoRM11E-G013 15-Jun-09 0 17 11.1 East Side 94 JT -- -- -- -- YesRM11E-G014 6-May-09 0 22 11.1 Nav Channel 12 JT -- -- -- -- NoRM11E-G015 16-Jun-09 0 29 11.2 East Side 120 T 640 T 53 JT 0.0013 J 0.00251 J 0.000531 J YesRM11E-G016 7-May-09 0 28 11.2 East Side 11 JT -- -- -- -- -- NoRM11E-G017 7-May-09 0 26 11.2 Nav Channel 410 JT -- -- -- -- -- YesRM11E-G018 7-May-09 0 25 11.2 East Side 22 JT 330 JT 4 JT 0.000292 J 0.000186 J 0.000162 U NoRM11E-G019 16-Jun-09 0 23 11.2 East Side 110 T -- -- -- -- -- Yes

Cleanup Level (ug/kg)

Focused COC Concentrations (ug/kg)

Portland Harbor ROD Screening Criteria

RI Surface Sediment Samples

Site-Wide RALs (ug/kg)PTW Thresholds (ug/kg)

Navigation Channel RALs (ug/kg)


Page 17 of 36



Upper Depth (cm)

Lower Depth (cm)


Exceedances?9

75 13000 160 0.0008 0.2 0.0006 --

200 - 7050 0.01 0.2 0.01 --

1000 170000 650 0.003 1 0.002 --


Portland Harbor ROD Screening CriteriaSite-Wide RALs (ug/kg)

PTW Thresholds (ug/kg)Navigation Channel RALs (ug/kg)

RM11E-G020 7-May-09 0 27 11.2 Nav Channel 91 JT -- -- -- -- -- NoRM11E-G021 7-May-09 0 25 11.2 Nav Channel 9.2 JT 89 JT 1.9 JT 0.000117 U 0.0000616 U 0.000163 U NoRM11E-G022 7-May-09 0 21 11.3 East Side 180 JT 1800 T 16 T 0.000733 J 0.000626 J 0.000552 J YesRM11E-G023 7-May-09 0 17 11.3 East Side 1000 JT 0.88 JT -- -- -- YesRM11E-G024 7-May-09 0 20 11.3 Nav Channel 77 JT 120 JT 4.7 T 0.0000818 U 0.000139 J 0.000202 U NoRM11E-G025 8-May-09 0 25 11.3 Nav Channel 96 JT -- -- -- -- -- NoRM11E-G026 8-May-09 0 17 11.3 East Side 1400 JT 2800 T 8.2 JT 0.00016 U 0.000215 J 0.000264 J YesRM11E-G027 8-May-09 0 22 11.3 East Side 140 JT 6.4 JT -- -- -- YesRM11E-G028 8-May-09 0 28 11.3 Nav Channel 380 JT 800 T 23 JT 0.000754 J 0.000676 J 0.000378 J YesRM11E-G029 12-May-09 0 19 11.3 East Side 2300 JT 2200 JT 31 T 0.0003 J 0.000482 J 0.0000895 U YesRM11E-G030 8-May-09 0 20 11.3 East Side 190 JT -- -- -- -- -- YesRM11E-G031 8-May-09 0 23 11.3 Nav Channel 18 JT -- -- -- -- -- NoRM11E-G032 8-May-09 0 20 11.3 Nav Channel 9 JT -- -- -- -- -- NoRM11E-G033 13-May-09 0 25 11.4 East Side 2000 JT 240 JT 0.44 JT 0.00518 J 0.0000512 U 0.00163 J YesRM11E-G035 8-May-09 0 26 11.3 Nav Channel 7.3 JT -- -- -- -- -- NoRM11E-G036 15-Jun-09 0 25 11.4 East Side 1300 JT 960 T 3.8 JT 0.000463 J 0.000806 J 0.0000591 U YesRM11E-G037 13-May-09 0 28 11.4 Nav Channel 110 JT -- -- -- -- -- NoRM11E-G038 11-May-09 0 26 11.4 Nav Channel 6.5 JT -- -- -- -- -- NoRM11E-G039 15-Jun-09 0 28 11.4 East Side 22 JT 170 JT 2.1 JT 0.000294 J 0.000861 J 0.0000393 U NoRM11E-G040 13-May-09 0 22 11.4 Nav Channel 6.2 JT -- -- -- No

RM11E-G043 10 11-May-09 0 30 11.4 East Side 16 JT 570 T 2 JT 0.000916 J 0.000212 J 0.0000889 U YesRM11E-G063 15-Jun-09 0 26 11.2 Nav Channel 8.3 JT -- -- -- -- -- NoRM11E-G064 15-Jun-09 0 15 11.4 East Side 1600 JT -- -- -- -- -- YesRM11E-G065 18-Jun-09 0 28 11.2 East Side 170 JT -- -- -- -- -- YesRM11E-G066 18-Jun-09 0 23 11.3 East Side 350 JT 170 JT 25 T 0.00054 U 0.000121 U 0.000167 U YesRM11E-G067 15-Jun-09 0 26 11.3 East Side 56 T 220 JT 11 JT 0.000252 J 0.000283 J 0.000187 J NoRM11E-G068 31-Oct-13 0 26 10.9 Nav Channel 97 JT -- 2.7 JT -- -- -- NoRM11E-G069 30-Oct-13 0 24 10.8 Nav Channel 64 T -- -- -- -- -- NoRM11E-G070 30-Oct-13 0 8 10.9 Nav Channel 430 T -- -- -- -- -- YesRM11E-G071 30-Oct-13 0 24 10.9 Nav Channel 180 JT -- -- -- -- -- NoRM11E-G072 30-Oct-13 0 26 10.9 East Side 38 T -- -- 0.000401 J 0.000663 J 0.000316 U NoRM11E-G073 30-Oct-13 0 22 10.9 East Side 23 JT -- -- -- -- -- NoRM11E-G074 30-Oct-13 0 26 10.9 Nav Channel 80 T -- -- -- -- -- NoRM11E-G075 31-Oct-13 0 17 10.9 East Side 49 T -- -- 0.000325 J 0.000972 J 0.000264 U NoRM11E-G076 31-Oct-13 0 25 11.1 East Side 110 JT -- 2.6 JT -- -- -- Yes


Page 18 of 36



Upper Depth (cm)

Lower Depth (cm)


Exceedances?9

75 13000 160 0.0008 0.2 0.0006 --

200 - 7050 0.01 0.2 0.01 --

1000 170000 650 0.003 1 0.002 --




RM11E-G077 31-Oct-13 0 22 11.2 Nav Channel 290 T -- 0.39 T -- -- -- YesRM11E-G078 2-May-14 0 30.5 11.2 East Side 340 JT -- -- -- -- -- YesRM11E-G079 31-Oct-13 0 23 11.2 Nav Channel 1400 JT -- 0.7 T -- -- -- YesRM11E-G080 2-May-14 0 30.5 11.3 East Side 140 T -- -- -- -- -- YesRM11E-G081 2-May-14 0 30.5 11.3 East Side 160 JT -- -- -- -- YesRM11E-G082 31-Oct-13 0 20 11.3 Nav Channel 910 T -- 2.2 JT -- -- -- YesRM11E-G083 1-May-14 0 24 11.4 East Side 26 JT -- -- -- -- -- NoRM11E-G084 1-May-14 0 20 11.4 East Side 160 T -- 9.8 JT -- -- -- YesRM11E-G085 2-May-14 0 8 11.4 East Side 69 JT -- -- -- -- -- NoRM11E-G086 2-May-14 0 8 11.4 East Side 47 JT -- -- -- -- -- NoRM11E-G087 2-May-14 0 26 11.1 East Side 310 T -- -- 0.00113 J 0.000634 J 0.000225 U YesRM11E-G088 1-May-14 0 21.5 11.4 East Side 11 JT -- -- 0.0000899 U 0.000109 U 0.000274 U NoRM11E-G089 1-May-14 0 24 11.4 East Side 23 JT -- -- -- -- -- NoRM11E-PW001-SED 20-Oct-14 0 25.4 11.2 Nav Channel 312 JT -- -- -- -- -- YesRM11E-PW002-SED 20-Oct-14 0 30.5 11.3 East Side 481 JT -- -- -- -- -- YesRM11E-PW003-SED 20-Oct-14 0 24.4 11.3 East Side 1000 JT -- -- -- -- -- YesRM11E-PW004-SED 20-Oct-14 0 30.5 11.3 East Side 1180 JT -- -- -- -- -- YesRM11E-PW005-SED 20-Oct-14 0 30.5 11.4 Nav Channel 159 JT -- -- -- -- -- NoRM11E-PW006-SED 20-Oct-14 0 30.5 11.4 East Side 3.53 JT -- -- -- -- -- No

RM11E-SL001 22-Sep-09 0 10 11.1 East Side 20 T 180 JT 3.3 JT 0.0000933 J 0.0000443 U 0.000161 U NoRM11E-SL002 22-Sep-09 0 10 11.1 East Side 30 T 3000 T 1.8 JT 0.000317 J 0.000783 J 0.0000837 U NoRM11E-SL003 22-Sep-09 0 10 11.1 East Side 6.7 JT 490 T 1.2 JT 0.000283 J 0.000407 J 0.000087 U NoRM11E-SL004 22-Sep-09 0 15 11.2 East Side 30 T 67000 JT 12 JT 0.00131 J 0.00114 J 0.00292 YesRM11E-SL005 22-Sep-09 0 9 11.2 East Side 81 T 470 JT 7 JT 0.00128 J 0.00107 J 0.000323 J YesRM11E-SL006 22-Sep-09 0 5 11.2 East Side 18 T 50 JT 1.7 JT 0.000187 J 0.0000809 U 0.0000832 U NoRM11E-SL007 22-Sep-09 0 12 11.3 East Side 37 T 89 JT 4.4 JT 0.00025 J 0.00015 U 0.0000897 U NoRM11E-SL008 22-Sep-09 0 10 11.3 East Side 92 T 420 JT 7 JT 0.000483 J 0.000913 J 0.000853 J YesRM11E-SL009 22-Sep-09 0 20 11.3 East Side 96 JT 750 T 9 JT 0.000711 J 0.000454 J 0.000618 J YesRM11E-SL010 22-Sep-09 0 15 11.5 East Side 25 T 1400 T 3.6 JT 0.000969 J 0.0018 J 0.000586 J YesRM11E-SL011 22-Sep-09 0 20 11.4 East Side 49 T 370 T 6 JT 0.00164 J 0.0011 J 0.000326 J YesRM11E-SL012 23-Sep-09 0 14 11.3 East Side 65 T 6500 T 5.1 JT 0.00113 J 0.00281 J 0.000416 J YesRM11E-SL013 23-Sep-09 0 10 11.4 East Side 76 T 2500 T 3.5 JT 0.000803 J 0.000437 U 0.00048 U YesRM11E-SL014 23-Sep-09 0 12 11.4 East Side 49 T 840 T 15 T 0.000465 U 0.00112 J 0.000607 U NoRM11E-SL015 23-Sep-09 0 25 11.3 East Side 66 JT 1700 T 71 JT 0.000968 J 0.00257 J 0.000372 J Yes

RI Shoreline Surface Sediment Samples


Page 19 of 36



Upper Depth (cm)

Lower Depth (cm)


Exceedances?9

75 13000 160 0.0008 0.2 0.0006 --

200 - 7050 0.01 0.2 0.01 --

1000 170000 650 0.003 1 0.002 --




RM11E-SL016 23-Sep-09 0 25 11.3 East Side 13 JT 59 JT 0.13 UT 0.000292 U 0.000151 U 0.00039 U NoRM11E-SL017 23-Sep-09 0 15 11.3 East Side 77 JT 1700 T 12 JT 0.0000617 U 0.0000597 U 0.0000686 U YesRM11E-SL018 23-Sep-09 0 15 11.3 East Side 11 T 270 JT 0.57 JT 0.000205 J 0.000744 J 0.000128 U NoRM11E-SL019 23-Sep-09 0 20 11.4 East Side 160 T 4100 T 24 JT 0.000295 J 0.00104 J 0.000157 J YesRM11E-SL020 23-Sep-09 0 20 11.4 East Side 380 T 360 JT 30 T 0.00037 J 0.00064 J 0.0000938 U YesRM11E-SL021 27-Oct-09 0 20 11.3 East Side 160 T 700 JT 20 JT 0.000695 J 0.000653 J 0.000322 J YesRM11E-SL022 27-Oct-09 0 18 11.3 East Side 40 T 840 JT 8.6 JT 0.00064 J 0.000584 J 0.00083 J YesRM11E-SL023 27-Oct-09 0 22 11.3 East Side 74 T 440 JT 9.5 JT 0.0000945 U 0.000108 U 0.000171 U No

WLCGWI04GNVV01 21-Sep-04 0 10 11.3 East Side 4700 T -- -- -- -- -- YesWLCGWI04GNVV02 21-Sep-04 0 10 11.2 East Side 440 T -- -- -- -- -- YesWLCGWI04GNVV03 24-Sep-04 0 10 11.2 East Side 2400 T -- -- -- -- -- YesWLCGWI04GNVV04 21-Sep-04 0 10 11.1 East Side 320 T -- -- -- -- -- Yes

WLCAYH00SD01SD01S 12 9-Aug-00 0 20 11 East Side 66 T -- -- -- -- -- NoWLCDRD05PG06363 13 23-May-05 0 24 10.9 East Side 200 JT 1300 T 19 NJT -- -- -- Yes

18031001 27-Mar-18 0 < 30 11.0 East Side 6.3 T 1600 JT 7.8 JT -- -- -- No18031002 27-Mar-18 0 < 30 11.0 East Side 8 T 1900 JT 1.2 UT -- -- -- No18031003 27-Mar-18 0 < 30 11.0 East Side 5.9 T 1100 JT 8.8 JT -- -- -- No18031004 27-Mar-18 0 < 30 11.0 East Side 6.3 T 280 JT 1.2 UT -- -- -- No18031005 27-Mar-18 0 < 30 11.0 East Side 6.9 JT 360 JT 0.57 UT -- -- -- No18031006 27-Mar-18 0 < 30 11.0 East Side 6.2 JT 2200 JT 5.2 JT -- -- -- No18031007 27-Mar-18 0 < 30 10.9 East Side 8.3 JT 9200 JT 8.4 JT -- -- -- No18031022 15

27-Mar-18 0 < 30 11.0 East Side 4.2 JT 300 JT 0.31 UT -- -- -- No

RM11E-SL035 31-Oct-13 0 20 11.3 East Side 36 T 650 JT 0.098 UT -- -- -- NoRM11E-SL036 31-Oct-13 0 30 11.3 East Side 72 T 3200 T 0.29 JT -- -- -- No

RM11E-SL028 22-Nov-13 0 30 11.1 East Side 32 JT 3200 JT 1.8 T -- -- -- NoRM11E-SL029 22-Nov-13 0 28 11.2 East Side 11 JT 41 UT 3.2 T -- -- -- NoRM11E-SL030 22-Nov-13 0 30 11.2 East Side 14 T 420 JT 1.5 T -- -- -- NoRM11E-SL031 22-Nov-13 0 23 11.3 East Side 24 JT 1200 JT 0.82 T -- -- -- NoRM11E-SL032 18-Nov-13 0 27 11.3 East Side 46 JT 2700 JT 2.7 T -- -- -- NoRM11E-SL033 18-Nov-13 0 29 11.4 East Side 170 T 6700 JT 5.8 T -- -- -- Yes

Post-Dredge Surface Sediment Characterization Samples 11

Other Surface Sediment Samples

RI Top of Bank Surface Soil Samples 16

RI Riverbank Surface Soil Samples (Collected in the Cove at RM 11.3) 16

Stan Herman Shoreline Surface Sediment Samples 14


Page 20 of 36



Upper Depth (cm)

Lower Depth (cm)


Exceedances?9

75 13000 160 0.0008 0.2 0.0006 --

200 - 7050 0.01 0.2 0.01 --

1000 170000 650 0.003 1 0.002 --




RM11E-SL034 18-Nov-13 0 29 11.4 East Side 2.1 UT 510 JT 1.7 T -- -- -- NoUB-101012 (GUB)14 10-Oct-12 0 15 11.3 East Side 61 T 8050 JT -- -- -- -- NoLB-101012 (GLB)14 10-Oct-12 0 15 11.3 East Side 260 T 1870 T -- -- -- -- Yes

18031008 27-Mar-18 0 < 30 11.0 East Side 5.2 JT 6500 JT 6.2 JT -- -- -- No18031009 27-Mar-18 0 < 30 11.0 East Side 5.6 JT 430 JT 0.94 UT -- -- -- No18031010 27-Mar-18 0 < 30 11.0 East Side 5.5 JT 590 JT 0.83 UT -- -- -- No18031011 27-Mar-18 0 < 30 11.0 East Side 6.6 JT 360 JT 7.2 JT -- -- -- No18031012 27-Mar-18 0 < 30 10.9 East Side 6.8 JT 570 JT 6.8 JT -- -- -- No18031013 27-Mar-18 0 < 30 11.0 East Side 5.9 JT 860 JT 0.89 UT -- -- -- No18031014 27-Mar-18 0 < 30 11.0 East Side 11 JT 1900 JT 5 JT 0.027 0.0073 U 0.006 Yes18031015 27-Mar-18 0 < 30 11.0 East Side 7.8 JT 460 JT 3.8 JT -- -- -- No18031016 27-Mar-18 0 < 30 10.9 East Side 8.7 JT 2300 JT 14 T 0.001 J 0.0016 U 0.00014 U Yes18031017 27-Mar-18 0 < 30 11.0 East Side 6.8 JT 3100 JT 16 JT 0.0016 J 0.002 U 0.0017 Yes18031018 27-Mar-18 0 < 30 11.0 East Side 11 JT 1300 JT 8.5 T 0.0023 J 0.0018 U 0.00063 J Yes18031019 27-Mar-18 0 < 30 11.0 East Side 7.9 JT 620 JT 5.1 T -- -- -- --18031020 27-Mar-18 0 < 30 11.0 East Side 5.8 JT 1500 JT 6.5 JT -- -- -- --18031021 27-Mar-18 0 < 30 10.9 East Side 14 T 8200 JT 87 JT 0.0012 J 0.0018 U 0.00032 J Yes

Notes:

3 Sum of Polychlorinated Biphenyls (PCBs) with non detected values included in calculation at half of the method detection limit. 4 Sum of Polycyclic Aromatic Hydrocarbons (PAHs) with non detected values included in calculation at half of the method detection limit. 5 Sum of six organochlorine DDx compounds with non detected values included in calculation at half of the method detection limit. 6PeCDD = 1,2,3,7,8-Pentachlorodibenzo-p-dioxin7 PeCDF = 2,3,4,7,8-Pentachlorodibenzofuran 8 TCDD = 2,3,7,8-Tetrachlorodibenzo-p-dioxin 9 Data were screened against RTs using half of the method detection limit for non-detected analytes.10 Material sampled in G043 was likely removed as part of the 2009 Cargill dredging event and is therefore excluded from figures but included for reference in this table.11 These post-dredge characterization samples were collected in September 2004 following the 2004 Glacier Dredging event and are thus representative of the post-dredge surface sediment collected from within the upper 10 cm of mudline.12 This surface sediment sample was collected in August 2000 as part of the Albina Yard Expanded Preliminary Assessment Data Report.13 This surface sediment samples was collected in May 2005 as part of the 2005 O&M Dredge Sediment Characterization14Dataset generated by third party and is not included in Portland Harbor database or provided datafile.

1 River mile shown reports the nearest downstream tenth of river mile in the Willamette River, as measured upstream from the confluence with the Columbia River. Therefore the river mile shown represents a range, from the river mile tenth that is shown to the next upstream tenth. For example "RM 11.3" represents samples collected between RM 11.3 and 11.4.2 River region indicates if the sample was collected within the federally authorized Navigation Channel or in the nearshore areas east of the Navigation Channel (i.e "East Side").

Stan Herman Riverbank Surface Soil Samples 14,16


Page 21 of 36



Upper Depth (cm)

Lower Depth (cm)


Exceedances?9

75 13000 160 0.0008 0.2 0.0006 --

200 - 7050 0.01 0.2 0.01 --

1000 170000 650 0.003 1 0.002 --




15This sample is a duplicate of Sample 18031005.

Notes (Continued):16 RTs do not apply to top of bank, monitoring well soil samples or non-erosive riverbank samples. CULs do not apply to top of bank or monitoring well samples. Comparisons to RTs is provided for reference purposes only.

COC = Contaminant of Concern

RT = Remediation Threshold

ug/kg=microgram per kilogram

Bold Values indicate detected results that exceed Cleanup Levels (CULs).

Highlighted values indicate detected results that exceed the RT as follows:

Exceeds RAL but not PTW

Exceeds PTW but not RAL

Exceeds PTW and RAL Note that yellow highlighting is used for PAHs that exceed RALs as there is no PTW value for PAHs.




N= The N-qualifier denotes that the identify of the analyte is presumptive and not definitive.


Page 22 of 36

Table 2-7Focused COC Concentrations in Subsurface Sediment and Soil


Upper Depth (cm)

Lower Depth (cm)

River Mile1 River Region2 Total

PCBs3 Total PAH4 Total DDx5 PeCDD6 PeCDF7 TCDD8 Any RT Exceedances?9

75 13000 160 0.0008 0.2 0.0006 --200 - 7050 0.01 0.2 0.01 --

1000 170000 650 0.003 1 0.002 --9 23000 6.1 0.0002 0.0003 0.0002 --

LW3-C777-B 9-Jan-08 30 122 11.2 Nav Channel 0.98 JT 0.75 UT 0.18 UT -- -- -- No

LW3-C777-C 9-Jan-08 122 215 11.2 Nav Channel 0.01 UT 0.75 UT 0.18 UT -- -- -- No

LW3-C777-D 9-Jan-08 215 252 11.2 Nav Channel 0.01 UT 0.75 UT 0.18 UT -- -- -- No

LW3-C778-B 9-Jan-08 30 118 11.3 Nav Channel 0.42 JT 0.75 UT 0.18 UT -- -- -- No

LW3-C778-C 9-Jan-08 118 241 11.3 Nav Channel 0.42 T 0.75 UT 0.18 UT -- -- -- No

LW3-C779-B 9-Jan-08 30 97 11.3 Nav Channel 82 JT 7.7 JT 3.4 JT -- -- -- No

LW3-C779-C 9-Jan-08 97 154 11.3 Nav Channel 1.5 JT 4.1 JT 0.18 UT -- -- -- No

LW3-C779-E 9-Jan-08 212 293 11.3 Nav Channel 0.0097 UT 0.85 UT 0.18 UT -- -- -- No

LW3-UC01-B 7-Feb-07 30 93 11.1 East Side 480 JT 2000 T 140 NJT -- -- -- Yes

LW3-UC02-B 7-Feb-07 30 90 11.2 Nav Channel 2.2 UT 280 JT 0.69 UT -- -- -- No

LW3-UC02-C 7-Feb-07 90 216 11.2 Nav Channel 2 UT 9.1 JT 0.27 UT -- -- -- No

LW3-UC03-B 8-Feb-07 30 120 11.3 Nav Channel 2400 JT 2300 T 120 NJT -- -- -- Yes

LW3-UC03-C 8-Feb-07 120 242 11.3 Nav Channel 190 T 2300 T 19 NJT -- -- -- No

LW3-UC03-D 8-Feb-07 242 308 11.3 Nav Channel 64 T 1600 T 11 NJT -- -- -- No

RM11E-C001-B 23-May-09 30.5 91.4 11.1 East Side 6.2 JT -- -- -- -- -- No

RM11E-C001-C 23-May-09 91.4 148 11.1 East Side 18 T -- -- -- -- -- No

RM11E-C002-B 23-May-09 30.5 91.4 11.1 Nav Channel 170 T -- -- -- -- -- No

RM11E-C002-C 23-May-09 91.4 152.4 11.1 Nav Channel 31 T -- -- -- -- -- No

RM11E-C002-D 23-May-09 152.4 166 11.1 Nav Channel 1 UT -- -- -- -- -- No

RM11E-C003-B 21-May-09 30.5 91.4 11.1 East Side 300 T 3300 T 43 JT 0.00549 J 0.0169 0.00169 Yes

RM11E-C003-C 21-May-09 91.4 152.4 11.1 East Side 8.3 T -- -- -- -- -- No

RM11E-C003-D 21-May-09 152.4 172 11.1 East Side 970 JT 3900 T 56 T 0.00715 J 0.0199 0.00232 Yes

RM11E-C004-B 26-May-09 30.5 91.4 11.1 East Side 7.3 JT -- -- -- -- -- No

RM11E-C004-C 26-May-09 91.4 131 11.1 East Side 1 UT -- -- -- -- -- No

RM11E-C005-B 26-May-09 30.5 91.4 11.1 Nav Channel 1 UT -- -- -- -- -- No

RM11E-C005-C 26-May-09 91.4 152.4 11.1 Nav Channel 1 UT -- -- -- -- -- No

RM11E-C005-D 26-May-09 152.4 213.4 11.1 Nav Channel 1 UT -- -- -- -- -- No

RM11E-C006-B 20-May-09 30.5 90 11.1 East Side 28 T 92 JT 1.9 JT 0.0000808 J 0.0000947 J 0.0000801 U No

RM11E-C007-B 26-May-09 30.5 91.4 11.1 East Side 1 UT -- -- -- -- -- No

RM11E-C007-C 26-May-09 91.4 152.4 11.1 East Side 1 UT -- -- -- -- -- No

RM11E-C007-D 26-May-09 152.4 213.4 11.1 East Side 1 UT -- -- -- -- -- No


RI Subsurface Sediment Samples

Screening CriteriaSite-Wide RALs (ug/kg)

Navigation Channel RALs (ug/kg)PTW Thresholds (ug/kg)

Cleanup Level (ug/kg)


Page 23 of 36



Upper Depth (cm)

Lower Depth (cm)



75 13000 160 0.0008 0.2 0.0006 --200 - 7050 0.01 0.2 0.01 --

1000 170000 650 0.003 1 0.002 --







RM11E-C009-B 21-May-09 30.5 91.4 11.1 East Side 98 JT 1600 JT 7.3 T 0.000854 J 0.000749 J 0.0000306 U Yes


RM11E-C010-B 22-May-09 30.5 91.4 11.1 East Side 63 T -- -- -- -- -- No

RM11E-C010-C 22-May-09 91.4 152.4 11.1 East Side 11 JT -- -- -- -- -- No

RM11E-C010-D 22-May-09 152.4 169 11.1 East Side 1 UT -- -- -- -- -- No

RM11E-C011-B 27-May-09 30.5 91.4 11.1 Nav Channel 5.2 JT -- -- -- -- -- No



RM11E-C012-B 20-May-09 30.5 91.4 11.2 East Side 160 T 1400 T 33 JT 0.00116 J 0.00198 J 0.000781 J Yes

RM11E-C012-C 20-May-09 91.4 152.4 11.2 East Side 5.7 T -- -- -- -- -- No


RM11E-C012-E 20-May-09 213 274 11.2 East Side 1.3 UT -- -- -- -- -- No







RM11E-C015-B 21-May-09 30.5 91.4 11.2 East Side 120 T 1500 T 12 JT 0.00126 J 0.00161 J 0.000647 J Yes

RM11E-C015-C 21-May-09 91.4 152.4 11.2 East Side 180 T -- -- -- -- -- Yes

RM11E-C015-D 21-May-09 152.4 225 11.2 East Side 29 T -- -- -- -- -- No

RM11E-C016-B 22-May-09 30.5 91.4 11.2 East Side 12 T -- -- -- -- -- No







RM11E-C018-C 23-May-09 91.4 152 11.2 Nav Channel 1 UT -- -- -- -- -- No

RM11E-C019-B 21-May-09 30.5 91.4 11.3 East Side 210 T -- -- -- -- -- Yes


Page 24 of 36



Upper Depth (cm)

Lower Depth (cm)



75 13000 160 0.0008 0.2 0.0006 --200 - 7050 0.01 0.2 0.01 --

1000 170000 650 0.003 1 0.002 --





RM11E-C019-D 21-May-09 152.4 213.4 11.3 East Side 9000 T 2300 JT 25 JT 0.000459 JT 0.00088 JT 0.0000284 UT Yes

RM11E-C019-E 21-May-09 213 301 11.3 East Side 75 T -- -- -- -- -- Yes

RM11E-C020-B 22-May-09 30.5 91.4 11.3 East Side 240 JT 10 T -- -- -- Yes


RM11E-C021-B 19-May-09 30.5 91.4 11.3 Nav Channel 1 UT 8.4 JT 0.1 UT 0.0000248 U 0.0000163 U 0.0000249 U No



RM11E-C022-B 20-May-09 30.5 91.4 11.3 East Side 390 JT -- -- -- -- -- Yes

RM11E-C022-C 20-May-09 91.4 140 11.3 East Side 2800 T 4700 T 19 T 0.000842 J 0.00124 J 0.000526 J Yes

RM11E-C023-B 21-May-09 30.5 91.4 11.3 East Side 4300 T -- -- -- -- -- Yes


RM11E-C023-D 21-May-09 152.4 213.4 11.3 East Side 2200 JT -- -- -- -- -- Yes

RM11E-C023-E 21-May-09 213.4 301 11.3 East Side 670 T 1200 T 29 T 0.00137 J 0.00103 J 0.00145 J Yes

RM11E-C024-B 27-May-09 30.5 91.4 11.3 Nav Channel 1 UT 0.75 UT 0.1 UT 0.0000277 U 0.0000156 U 0.0000196 U No

RM11E-C024-C 27-May-09 91.4 152.4 11.3 Nav Channel 8.4 T -- -- -- -- -- No


RM11E-C025-B 22-May-09 30.5 91.4 11.3 East Side 56 JT 580 T 1.3 UT 0.000241 J 0.000313 J 0.0000194 U No

RM11E-C025-C 22-May-09 91.4 152.4 11.3 East Side 5.5 JT -- -- -- -- -- No





RM11E-C026-E 22-May-09 213.4 304.8 11.3 East Side 1.3 UT -- -- -- -- -- No

RM11E-C026-F 22-May-09 304.8 381 11.3 East Side 1.3 UT -- -- -- -- -- No

RM11E-C027-B 26-May-09 30.5 91.4 11.3 Nav Channel 8.3 T -- -- -- -- -- No






RM11E-C029-B 23-Jun-09 30.5 91.4 11.4 East Side 1.3 UT 4.1 JT 0.1 UT 0.0000431 UT 0.000135 JT 0.0000358 UT No

RM11E-C029-C 23-Jun-09 91.4 152.4 11.4 East Side 1.3 UT -- -- -- -- -- No


Page 25 of 36



Upper Depth (cm)

Lower Depth (cm)



75 13000 160 0.0008 0.2 0.0006 --200 - 7050 0.01 0.2 0.01 --

1000 170000 650 0.003 1 0.002 --




RM11E-C029-D 23-Jun-09 152.4 213.4 11.4 East Side 1.3 UT -- -- -- -- -- No

RM11E-C029-E 23-Jun-09 213.4 304.8 11.4 East Side 1.3 UT -- -- -- -- -- No

RM11E-C029-F 23-Jun-09 304.8 396.2 11.4 East Side 1.3 UT -- -- -- -- -- No

RM11E-C029-G 23-Jun-09 396.2 436 11.4 East Side 1.3 UT -- -- -- -- -- No




RM11E-C032-B 23-Jun-09 30.5 91.4 11.4 East Side 7.6 JT 240 JT 0.2 UT 0.000496 U 0.000112 U 0.000148 U No

RM11E-C032-C 23-Jun-09 91.4 152.4 11.4 East Side 1.3 UT -- -- -- -- -- No

RM11E-C032-D 23-Jun-09 152.4 213.4 11.4 East Side 1.3 UT -- -- -- -- -- No


RM11E-C032-F 23-Jun-09 304.8 341 11.4 East Side 1.3 UT -- -- -- -- -- No

RM11E-C033-B 18-May-09 30.5 91.4 11.4 East Side 64 JT -- -- -- -- -- No




RM11E-C034-C 20-May-09 91.4 157 11.4 Nav Channel 1 UT -- -- -- -- -- No


RM11E-C035-C 21-May-09 91.4 152.4 11.4 East Side 1 UT 1000 T 0.1 UT 0.0000434 U 0.0000429 U 0.0000451 U No





RM11E-C038-B 10 20-May-09 30.5 91.4 11.4 East Side 8.3 T 110 JT 0.68 JT 0.00013 J 0.000131 J 0.0000643 U No



RM11E-C047-B 23-Jun-09 30.5 91.4 11.3 East Side 220 T 490 JT 0.88 JT 0.000889 U 0.000298 U 0.0011 U Yes

RM11E-C047-C 23-Jun-09 91.4 152.4 11.3 East Side 85 T -- -- -- -- -- Yes

RM11E-C047-D 23-Jun-09 152.4 213.4 11.3 East Side 20 T -- -- -- -- -- No


RM11E-C047-F 23-Jun-09 304.8 355 11.3 East Side 1.3 UT -- -- -- -- -- No

RM11E-C048-B (R1) 24-Jun-09 30.5 91.4 11.2 East Side 66 JT -- -- -- -- -- No

RM11E-C048-B (R2) 24-Jun-09 30.5 82 11.2 East Side 220 T -- -- -- -- -- Yes


Page 26 of 36



Upper Depth (cm)

Lower Depth (cm)



75 13000 160 0.0008 0.2 0.0006 --200 - 7050 0.01 0.2 0.01 --

1000 170000 650 0.003 1 0.002 --




RM11E-C048-C (R1) 24-Jun-09 91.4 134 11.2 East Side 38 JT 27000 T 14 JT 0.00852 0.0163 0.00306 Yes

RM11E-SL015-90-120 23-Sep-09 90 120 11.3 East Side 6.9 JT 45 JT 0.59 JT 0.000329 U 0.000412 U 0.000659 U No

WLCGWF03GNVC01Z1 11 6-Jun-03 54.86 85.34 11.3 East Side 900 T -- -- -- -- -- Yes

WLCGWF03GNZCOMP2003 11 6-Jun-03 54.86 88.39 11.2 East Side 860 T -- -- -- -- -- Yes

WLCGWF03GNVC03Z1 11 6-Jun-03 57.91 88.39 11.2 East Side 88 T -- -- -- -- -- Yes

CLD-WR-01z 12,16 29-Jun-09 Unknown 150 11.4 East Side 854 T 408 T 9.8 T -- -- -- Yes

CLD-WR-02z 12,16 29-Jun-09 Unknown 150 11.4 East Side 3.66 UT 506 T 0.943 UT -- -- -- No

WLCT0I98ISC2ISC2 13 15-Sep-98 91 152 11.4 East Side 740 T 1200 AT 2 AUT -- -- -- Yes

WLCAYH00SD01SD01D 14 9-Aug-00 30 60 11 East Side 20 UT -- -- -- -- -- No

WLR0797WRCD40RCD40A 15 24-Jul-97 0 61 11.3 Nav Channel 130 T 28 JT 24 AT -- -- -- No

RM11E-MWS001-5_24' 21-Nov-13 152 732 11.3 East Side 600 T 2100 JT 2 T -- -- -- Yes

RM11E-MWS001-24_29' 21-Nov-13 732 884 11.3 East Side 32 T 190 JT 1.7 T -- -- -- No

RM11E-MWS002s-5_20' 20-Nov-13 152 610 11.3 East Side 53 JT 910 JT 25 T -- -- -- No

RM11E-MWS002s-20_25' 20-Nov-13 610 762 11.3 East Side 2.1 UT 4.1 UT 0.28 T -- -- -- No

RM11E-MWS004-5_24' 22-Nov-13 152 732 11.4 East Side 17 T 340 JT 3.2 T -- -- -- No

RM11E-MWS004-24_29' 22-Nov-13 732 884 11.4 East Side 2.1 UT 32 JT 0.24 JT -- -- -- No

RM11E-MWS005-5_21' 22-Nov-13 152 640 11.1 East Side 88 T 760 JT 3 T -- -- -- Yes

RM11E-MWS005-21_26' 22-Nov-13 640 792 11.1 East Side 2.1 UT 1000 JT 0.22 JT -- -- -- No

Notes:

3 Sum of Polychlorinated Biphenyls (PCBs) with non detected values included in calculation at half of the method detection limit. 4 Sum of Polycyclic Aromatic Hydrocarbons (PAHs) with non detected values included in calculation at half of the method detection limit. 5 Sum of six organochlorine DDx compounds with non detected values included in calculation at half of the method detection limit. 6PeCDD = 1,2,3,7,8-Pentachlorodibenzo-p-dioxin7 PeCDF = 2,3,4,7,8-Pentachlorodibenzofuran 8 TCDD = 2,3,7,8-Tetrachlorodibenzo-p-dioxin 9 Data were screened against RTs using half of the method detection limit for non-detected analytes.

RI Monitoring Well Soil Boring Samples 17

1 River mile shown reports the nearest downstream tenth of river mile in the Willamette River, as measured upstream from the confluence with the Columbia River. Therefore the river mile shown represents a range, from the river mile tenth that is shown to the next upstream tenth. For example "RM 11.3" represents samples collected between RM 11.3 and 11.4.2 River region indicates if the sample was collected within the federally authorized Navigation Channel or in the nearshore areas east of the Navigation Channel (i.e "East Side").

Private Post-Dredge Subsurface Sediment Characterization Samples

Other Private Subsurface Sediment Samples

RI Subsurface Shoreline Sediment Samples


Page 27 of 36



Upper Depth (cm)

Lower Depth (cm)



75 13000 160 0.0008 0.2 0.0006 --200 - 7050 0.01 0.2 0.01 --

1000 170000 650 0.003 1 0.002 --




Notes (Continued):10 Material sampled in C038-B was likely removed as part of the 2009 Cargill dredging event and is therefore excluded from figures but included for reference in this table.

14 This surface sediment samples was collected in August 2000 as part of the Albina Yard Expanded Preliminary Assessment Data Report.15 This subsurface sediment samples was collected in July1997 as part of the CRCD - Willamette River Channel Deepening.16Dataset generated by third party and is not included in Portland Harbor database or provided datafile. 17RTs and CULs do not apply to monitoring well soil samples. Comparisons to RTs and CULs are provided for reference purposes only.


RT = Remediation Threshold

ug/kg=microgram per kilogram

Bold Values indicate detected results that exceed Cleanup Levels (CULs).

Highlighted values indicate detected results that exceed the RT as follows:

Exceeds RAL but not PTW

Exceeds PTW but not RAL

Exceeds PTW and RAL Note that yellow highlighting is used for PAHs that exceed RALs as there is no PTW value for PAHs.




N= The N-qualifier denotes that the identify of the analyte is presumptive and not definitive.

18 This DOI evaluation includes Remedial Investigation (RI) data collected by the City of Portland, RM11E Group, and Lower Willamette Group (LWG) and data collected by other parties. The DOI evaluation excludes samples representative of dredged material; however, it does include the predicted post-dredge leave surface data, where available, including the results from the 2004 Glacier and the 2002 and 2009 Cargill dredging events. These retained samples were obtained prior to maintenance dredging events that are considered to represent post-dredge surfaces (a.k.a. leave surface). While the “leave surface” characterization samples are included in this BODR and DOI evaluation out of conservatism, it is recognized that dredging activities may have affected contaminant concentrations (due to actual dredging depths achieved or residuals deposition) and applicability to current conditions is uncertain; therefore, these data may not represent the DOI in these sample areas and additional sampling will be required to refine the DOI during RD. As new sediment samples are collected during RD Sediment Characterization in the areas where these "leave surface "samples were collected, the new data will replace the "leave surface" data (see Section 2.7.3).

11 These dredge characterization samples were collected in June 2003 prior to the 2004 Glacier Dredging event and were collected with the intention of representing the upper approximately 30 cm (1 foot) of the post-dredge surface. Given that these data were collected from the lower-half of a subsurface core and the actual dredge depths are uncertain, the data is retained as subsurface data with the DOI reported based on the initial sample depth measurements. This approach may over-estimate the actual DOI.

12 These dredge characterization samples were collected in June 2009 prior to the 2009 Cargill Dredging event and were collected from the lower portion of two five-foot cores that were collected with the intention of representing the post-dredge surface. Note that these data are not included in the Portland Harbor or RM11E Database and were added to this evaluation based on the Draft Sediment Characterization Report for Maintenance Dredging at Willamette River (RM 11.4; Northern Resources Consulting, 2009). Given that these data were collected from the lower-half of a subsurface core and the actual dredge depths are uncertain, the data is retained as subsurface data with the DOI reported based on the initial sample measurements. This approach may over-estimate the actual DOI.

13 This dredge characterization sample was collected in 1998 prior to the 2002 Cargill Dredging event and was collected with the intention of representing the upper approximately 61 cm (2 feet) of the post-dredge surface. Note that the sample was a composite of the post-dredge surface from two separate cores taken at the front and back of a ship that was in berth at the time. The sample location shown in the figures at the stern of the ship, where the PCB concentrations were likely to be higher. Given that these data were collected from the lower-half of a subsurface core and the actual dredge depths are uncertain, the data is retained as subsurface data with the DOI reported based on the initial sample measurements. This approach may over-estimate the actual DOI.


Page 28 of 36

Table 2-8Total PCB Depth of Impact in Sediment and Soil

Combined Sample IDEstimated Total

PCB DOI (ft)

Total PCB DOIDelineated

(yes/no)

LW3-C777/LW3-G777 0 YesLW3-C778/LW3-G778 1 YesLW3-C779/LW3-G779 1 YesLW3-UC01/LW3-UG01 > 3 NoLW3-UC02/LW3-UG02/RM11E-G079/RM11E-PW001-SED 1 YesLW3-UC03/LW3-UG03/RM11E-G082 4 YesRM11E-C001/RM11E-G003 0 YesRM11E-C002/RM11E-G004 0 YesRM11E-C003/RM11E-G005 > 6 NoRM11E-C004/RM11E-G006 1 YesRM11E-C005/RM11E-G007 0 YesRM11E-C006/RM11E-G008 0 YesRM11E-C007/RM11E-G009/RM11E-G076 1 YesRM11E-C008/RM11E-G010 0 YesRM11E-C009/RM11E-G012 3 YesRM11E-C010-R2/RM11E-G013 1 YesRM11E-C011/RM11E-G014 0 YesRM11E-C012/RM11E-G015 3 YesRM11E-C013/RM11E-G016 0 YesRM11E-C014/RM11E-G017/RM11E-G077 1 YesRM11E-C015/RM11E-G018 5 YesRM11E-C016/RM11E-G019 1 YesRM11E-C017/RM11E-G020 0 YesRM11E-C018/RM11E-G021 0 YesRM11E-C019/RM11E-G022/RM11E-PW002-SED > 10 NoRM11E-C020/RM11E-G023 3 YesRM11E-C021/RM11E-G024 0 YesRM11E-C022/RM11E-G026/RM11E-PW003-SED > 5 NoRM11E-C023/RM11E-G027/RM11E-PW004-SED > 10 NoRM11E-C024/RM11E-G028/RM11E-PW005-SED 1 YesRM11E-C025/RM11E-G029 1 YesRM11E-C026/RM11E-G030 1 YesRM11E-C027/RM11E-G031 0 YesRM11E-C028/RM11E-G032 0 Yes

RM11E-C029/RM11E-G033/RM11E-PW006-SED 1 YesRM11E-C031/RM11E-G035 0 YesRM11E-C032/RM11E-G036/RM11E-G084 1 YesRM11E-C033 1 YesRM11E-C034/RM11E-G038 0 YesRM11E-C035/RM11E-G039/RM11E-G088 0 YesRM11E-C036/RM11E-G040 0 Yes

RM11E-C038/RM11E-G043 2 0 YesRM11E-C047/RM11E-G066 5 YesRM11E-C048-R1/RM11E-G065 1 YesRM11E-SL015 0 Yes

RM11E-C048-R2 > 3 NoRI Surface Sediment Samples (without any co-located subsurface sediment data)

RI Subsurface Sediment Samples (without any co-located surface sediment data)

RI Collocated Surface/Subsurface Sediment Samples 1


Page 29 of 36



PCB DOI (ft)


(yes/no)LW2-G516 0 YesLW3-G771 0 YesLW3-G776 > 1 NoLW3-GCA11E > 1 NoLW3-GCRSP11E 0 YesRM11E-G001 0 YesRM11E-G002 0 YesRM11E-G011 0 YesRM11E-G025 0 YesRM11E-G037 0 YesRM11E-G063 0 YesRM11E-G064 > 1 NoRM11E-G067 0 YesRM11E-G068 0 YesRM11E-G069 0 YesRM11E-G070 > 1 NoRM11E-G071 0 YesRM11E-G072 0 YesRM11E-G073 0 YesRM11E-G074 0 YesRM11E-G075 0 YesRM11E-G078 > 1 NoRM11E-G080 > 1 NoRM11E-G081 > 1 NoRM11E-G083 0 YesRM11E-G085 0 YesRM11E-G086 0 YesRM11E-G087 > 1 NoRM11E-G089 0 Yes

RM11E-SL001 0 YesRM11E-SL002 0 YesRM11E-SL003 0 YesRM11E-SL004 0 YesRM11E-SL005 > 1 NoRM11E-SL006 0 YesRM11E-SL007 0 YesRM11E-SL008 > 1 NoRM11E-SL009 > 1 NoRM11E-SL010 0 YesRM11E-SL011 0 YesRM11E-SL012 0 YesRM11E-SL013 > 1 NoRM11E-SL014 0 YesRM11E-SL016 0 YesRM11E-SL017 > 1 NoRM11E-SL018 0 YesRM11E-SL019 > 1 NoRM11E-SL020 > 1 No

RI Shoreline Surface Sediment Samples


Page 30 of 36



PCB DOI (ft)


(yes/no)RM11E-SL021 > 1 NoRM11E-SL022 0 YesRM11E-SL023 0 Yes

WLCAYH00SD01SD01D/WLCAYH00SD01SD01S3 0 Yes

WLR0797WRCD40RCD40A4 0 Yes

WLCDRD05PG063635 > 1 No

WLCGWF03GNZCOMP20036/WLCGWI04GNVV027 > 3 No

WLCGWF03GNVC01Z16 > 3 NoWLCGWF03GNVC03Z16 > 3 NoCLD-WR-01z8,9 > 3 NoCLD-WR-02z8,9,10 0 YesWLCT0I98ISC2ISC211 > 5 No

WLCGWI04GNVV01 > 1 NoWLCGWI04GNVV03 > 1 NoWLCGWI04GNVV04 > 1 No

18031001 0 Yes18031002 0 Yes18031003 0 Yes18031004 0 Yes18031005 0 Yes18031006 0 Yes18031007 0 Yes18031022 0 Yes

RM11E-SL035 0 YesRM11E-SL036 0 Yes

RM11E-SL028 0 YesRM11E-SL029 0 YesRM11E-SL030 0 YesRM11E-SL031 0 YesRM11E-SL032 0 YesRM11E-SL033 > 1 NoRM11E-SL034 0 YesUB-101012 (GUB) 0 YesLB-101012 (GLB) > 1 No

18031008 0 Yes18031009 0 Yes18031010 0 Yes18031011 0 Yes

Post-Dredge Subsurface Sediment Characterization Samples

Post-Dredge Surface Sediment Characterization Samples 7

Stan Herman Shoreline Surface Sediment Samples 9, 12

Stan Herman Surface Soil Samples 9, 12

Co-located Post-Dredge Surface/Subsurface Sediment Characterization Samples

Other Surface Sediment Samples

Other Subsurface Sediment Samples

Other Co-located Surface/Subsurface Sediment Samples

RI Top of Bank Surface Soil Samples 12

RI Shoreline Surface Soil Samples 12


Page 31 of 36



PCB DOI (ft)


(yes/no)18031012 0 Yes18031013 0 Yes18031014 0 Yes18031015 0 Yes18031016 0 Yes18031017 0 Yes18031018 0 Yes18031019 0 Yes18031020 0 Yes18031021 0 Yes

Notes:

9 Dataset generated by third party and is not included in Portland Harbor database or provided datafile. 10 CLD-WR-02z depth of impact determined based on co-located sample CLD-WR-02c, that also had concentrations that were less than RTs but was dredged and therefore excluded from this evaluation.

8 These dredge characterization samples were collected in June 2009 prior to the 2009 Cargill Dredging event and were collected from the lower portion of two five-foot cores that were collected with the intention of representing the post-dredge surface. Note that these data are not included in the Portland Harbor or RM11E Database and were added to this evaluation based on the Draft Sediment Characterization Report for Maintenance Dredging at Willamette River (RM 11.4; Northern Resources Consulting, 2009). Given that these data were collected from the lower-half of a subsurface core and the actual dredge depths are uncertain, the data is retained as subsurface data with the DOI reported based on the initial sample measurements. This approach may over-estimate the actual DOI.

7 These post-dredge characterization samples were collected in September 2004 following the 2004 Glacier Dredging event and are thus representative of the post-dredge surface sediment collected from within the upper 10 cm of mudline.

6 This dredge characterization samples was collected in June 2003 prior to the 2004 Glacier Dredging event and were collected with the intention of representing the upper approximately 30 cm (1 foot) of the post-dredge surface. Given that these data were collected from the lower-half of a subsurface core and the actual dredge depths are uncertain, the data is retained as subsurface data with the DOI reported based on the initial sample depth measurements. This approach may over-estimate the actual DOI.

5 This surface sediment samples was collected in May, 2005 as part of the 2005 O&M Dredge Sediment Characterization.

4 This surface sediment sample was collected in July 1997 as part of the CRCD - Willamette River Channel Deepening project.

3 This co-located surface/subsurface sediment sample pair was collected in August 2000 as part of the Albina Yard Expanded Preliminary Assessment Data Report.

1 Collocated surface and subsurface samples were collected within 20 feet of each other. The subsurface sample location coordinates were used as the collocated sample location shown in Figure 2-24.2 Material sampled in G043 and C038-B was likely removed as part of the 2009 Cargill Dredging Event. However, given that the actual dredge depth is unknown and only the surface sediment (G043) sample exceeded RALs, then this co-located location is included in the DOI evaluation with a delineated DOI of 1 ft, which may over-estimate the actual DOI.


Page 32 of 36



PCB DOI (ft)


(yes/no)

Notes (Continued):

12RTs do not apply to monitoring well soil samples. Comparisons to RTs is provided for reference purposes only.

Data were screened against Remediation Thresholds (RTs) using half of the method detection limit for non-detected analytes.

11 This dredge characterization sample was collected in 1998 prior to the 2002 Cargill Dredging event and was collected with the intention of representing the upper approximately 61 cm (2 feet) of the post-dredge surface. Note that the sample was a composite of the post-dredge surface from two separate cores taken at the front and back of a ship that was in berth at the time. The sample location shown in the figures at the stern of the ship, where the PCB concentrations were likely to be higher. Given that these data were collected from the lower-half of a subsurface core and the actual dredge depths are uncertain, the data is retained as subsurface data with the DOI reported based on the initial sample measurements. This approach may over-estimate the actual DOI.

13 This DOI evaluation includes Remedial Investigation (RI) data collected by the City of Portland, RM11E Group, and Lower Willamette Group (LWG) and data collected by other parties. The DOI evaluation excludes samples representative of dredged material; however, it does include the predicted post-dredge leave surface data, where available, including the results from the 2004 Glacier and the 2002 and 2009 Cargill dredging events. These retained samples were obtained prior to maintenance dredging events that are considered to represent post-dredge surfaces (a.k.a. leave surface). While the “leave surface” characterization samples are included in this BODR and DOI evaluation out of conservatism, it is recognized that dredging activities may have affected contaminant concentrations (due to actual dredging depths achieved or residuals deposition) and applicability to current conditions is uncertain; therefore, these data may not represent the DOI in these sample areas and additional sampling will be required to refine the DOI during RD. As new sediment samples are collected during RD Sediment Characterization in the areas where these "leave surface "samples were collected, the new data will replace the "leave surface" data (see Section 2.7.3).


Page 33 of 36

Table 2-9Focused COC Concentrations in Groundwater

Sample Date PeCDD4 PeCDF5 TCDD6

Units ug/L ug/L ug/L ug/L ng/L ng/L ng/L ng/L ng/LCleanup Level 0.014 0.014 -- -- 1 1 -- -- --

Basis A/R A/R -- -- A A -- -- --RM11E-MW001 12/10/2013 0.019 T 0.0086 T 0.51 JT 0.16 JT 0.11 UT 0.11 UT NA NA NARM11E-MW001 4/14/2014 0.0074 NJT 0.0035 NJT 0.032 UT 0.032 UT 0.11 UT 0.11 UT NA NA NARM11E-MW002s 12/5/2013 0.0032 UT 0.0032 UT 0.26 JT 0.014 JT 0.11 UT 0.11 UT NA NA NARM11E-MW002s 4/15/2014 0.0011 UT 0.0011 UT 0.22 JT 0.054 JT 0.12 UT 0.12 UT NA NA NARM11E-MW003d 12/5/2013 0.0028 UT 0.0028 UT 0.24 JT 0.049 JT 0.13 UT 0.13 UT NA NA NARM11E-MW003d 4/15/2014 0.0057 UT 0.0057 UT 0.22 JT 0.032 JT 0.38 JT 0.14 JT NA NA NARM11E-MW004 12/5/2013 0.0039 UT 0.0039 UT 0.28 JT 0.095 JT 0.12 UT 0.12 UT NA NA NARM11E-MW004 4/15/2014 0.0096 NJT 0.0057 NJT 0.22 JT 0.04 JT 0.12 UT 0.12 UT NA NA NARM11E-MW005 12/5/2013 0.0029 UT 0.0029 UT 0.23 JT 0.048 JT 0.12 UT 0.12 UT NA NA NARM11E-MW005 4/14/2014 0.00098 UT 0.00098 UT 0.031 UT 0.031 UT 0.11 UT 0.11 UT NA NA NARM11E-MULT1007 12/6/2013 0.0026 UT 0.0026 UT 0.23 JT 0.048 JT 0.11 UT 0.11 UT NA NA NARM11E-MULT1007 4/14/2014 0.044 NJT 0.0092 NJT 0.29 JT 0.12 JT 0.57 JT 0.27 JT NA NA NARM11E-MULT89881 12/4/2013 0.0031 UT 0.0031 UT 0.25 JT 0.068 JT 0.11 UT 0.11 UT NA NA NARM11E-MULT89881 4/15/2014 0.0011 UT 0.0011 UT 0.23 JT 0.54 JT 0.14 UT 0.14 UT NA NA NA

Notes:Bold Values indicate detected results.

Highlighted values indicate detected results that exceed the cleanup level (CUL).

-- = No cleanup level was established for this focused COC in this sample medium.1 Sum of Polychlorinated Biphenyls (PCBs) with non detected values included in calculation at half of the method detection limit. 2 Sum of Polyaromatic Hydrocarbons (PAHs) with non detected values included in calculation at half of the method detection limit. 3 Sum of six organochlorine DDx compounds with non detected values included in calculation at half of the method detection limit. 4 PeCDD = 1,2,3,7,8-Pentachlorodibenzo-p-dioxin5 PeCDF = 2,3,4,7,8-Pentachlorodibenzofuran 6 TCDD = 2,3,7,8-Tetrachlorodibenzo-p-dioxin

Acronyms:A = ARAR based


FS = Feasibility Study

NA = Analytical data not available.

ng/L = nanograms per liter

R = Risk based

RI = Remedial Investigation

ug/L = micrograms per liter



N = The analysis indicates the presence of a PCB Aroclor that has been identified as “presumptively present”. As per EPA guidelines, the data validator reviewed the associated chromatograms and determined that while the pattern-matching quality was marginal and the presence of many non-target compounds was apparent, the presence of an Aroclor was strongly suggested, and the results were thus qualified as presumptively present "N".

Monitoring Well ID

Total PCBs1

(FS Calc; U=1/2)Total PAH2

(FS Calc; U=1/2)Total PAH

(RI Calc; U=0)Total DDx3

(FS Calc; U=1/2)Total DDx

(RI Calc; U=0)

Focused COC ConcentrationsTotal PCBs

(RI Calc; U=0)



Page 34 of 36

Table 2-10Estimated Total PCB Concentrations in Porewater

Sample DateTotal PCBs

(RI Calc1; U=0)Units ng/L

Cleanup Level 14Basis A/R

RM11E-PWP001A 30.0 10/20/2014 18.7RM11E-PWP004A 29.5 10/20/2014 34.7



Source of data is the Final Porewater Characterization Report, River Mile 11 East (SEE et al., 2015)


cm bml = centimeters below mudline

PCBs = Polychlorinated Biphenyls

R = Risk based


Passive Sampler Sediment Exposure

Depth (cm bml)Monitoring Well ID

1 RI Calc = This result was calculated using the Remedial Investigation (RI) data rules for the Portland Harbor as described in Section 7.3 of the Final Supplemental Remedial Investigation/Feasibility Study (RI/FS) Work Plan (GSI and DOF, 2013).

Calculations made and reported on detected PCB congeners only. Estimates are rounded to four decimal places. Performance reference compounds excluded from RI calculation sum.


Page 35 of 36

Table 2-11aEstimated Total PCB Concentrations in Surface Water(RM11E Supplemental RI/FS Results)

Sample DateTotal PCBs

(RI Calc1; U=0)Units ng/L

Cleanup Level 0.0064Basis A/R

RM11E-PWW001A 15 MIT 10/20/2014 0.966RM11E-PWW001B 15 ALS 10/20/2014 0.960RM11E-PWW002A 17 ALS 10/20/2014 1.04RM11E-PWW003A 17 ALS 10/20/2014 0.490RM11E-PWW004A 15.5 MIT 10/20/2014 1.91RM11E-PWW004B 16 ALS 10/20/2014 3.12RM11E-PWW005A 13 ALS 10/20/2014 0.290RM11E-PWW006A 15 ALS 10/20/2014 3.47



Source of data is the Final Porewater Characterization Report, River Mile 11 East (SEE et al., 2015)


ALS = ALS Environmental laboratory

cm aml = centimeters above mudline

MIT = Massachusetts Institute of Technology

PCBs = Polychlorinated Biphenyls

R = Risk based


Monitoring Well ID Lab

Passive Sampler Surface Water

Exposure Depth (cm aml)

Calculations made and reported on detected PCB congeners only. Estimates are rounded to four decimal places. Performance reference compounds excluded from RI calculation sum.

1 RI Calc = This result was calculated using the Remedial Investigation (RI) data rules for the Portland Harbor as described in Section 7.3 of the Final Supplemental Remedial Investigation/Feasibility Study (RI/FS) Work Plan (GSI and DOF, 2013).


Page 36 of 36

Table 2-11bFocused COC Concentrations in Surface Water(PHSS Round 3 RI Results)

Sample Date PeCDD4 PeCDF5 TCDD6

UnitsCleanup Level -- -- --

Basis -- -- --LW3-W2023-E WS 9/6/2006 76 JTLW3-W2023-E C+F WSXAD 9/6/2006 0.951 JT 22 JT 0.0989 JTLW3-W2023-E-C WSXADC 9/6/2006 0.288 JT 17 JT 0.0577 JT 0.00325 J 0.0037 J 0.00564 ULW3-W2023-E-F WSXADF 9/6/2006 0.664 JT 7.9 JT 0.0415 JT 0.009 J 0.008 J 0.008 ULW3-W3023-E WS 11/2/2006 27 UTLW3-W3023-E C+F WSXAD 11/2/2006 0.558 JT 62 JT 0.1 JTLW3-W3023-E-C WSXADC 11/2/2006 0.154 JT 51 JT 0.05 JT 0.016 J 0.013 U 0.012 ULW3-W3023-E-F WSXADF 11/2/2006 0.417 JT 15 JT 0.062 JT 0.042 J 0.027 J 0.014 U

LW3-W4023-E WS 3/3/2007 13 UTLW3-W4023-E C+F WSXAD 3/3/2007 0.170 JT 20.5 JT 0.62 JTLW3-W4023-E-C WSXADC 3/3/2007 0.072 JT 15.9 JT 0.18 JT 0.002 U 0.002 U 0.0026 ULW3-W4023-E-F WSXADF 3/3/2007 0.100 JT 5.6 JT 0.44 JT 0.012 J 0.008 U 0.007 U


Highlighted values indicate detected results that exceed the cleanup level (CUL). -- = No cleanup level was established for this focused COC in this sample medium.Samples are from a vertically integrated water column1 Sum of Polychlorinated Biphenyls (PCBs) with non detected values included in calculation at half of the method detection limit. 2 Sum of Polycyclic Aromatic Hydrocarbons (PAHs) with non detected values included in calculation at half of the method detection limit. 3 Sum of six organochlorine DDx compounds with non detected values included in calculation at half of the method detection limit. 4 PeCDD = 1,2,3,7,8-Pentachlorodibenzo-p-dioxin5 PeCDF = 2,3,4,7,8-Pentachlorodibenzofuran 6 TCDD = 2,3,7,8-Tetrachlorodibenzo-p-dioxin

Definition of sample matrix:WS = Surface water sample collected using peristaltic pumpWSXAD = Surface water sample collected using INFILTREX 300. Sample analyzed from water in XAD column + and water in 0.5µm glass fiber filter. WSXADC = Surface water sample collected using INFILTREX 300. Sample analyzed from water in XAD column. WSXADF = Surface water sample collected using INFILTREX 300. Sample analyzed from water in 0.5µm glass fiber filter.

Notes (Continued):Definition of data qualifiers:

J = The associated numerical value is an estimated quantity.U = The material was analyzed for, but was not detected. The associated numerical value is the method detection limit (MDL).


Sampled During

Stormwater Event

Sampled During Low River Flow

Sampled During High River Flow

7 Samples were collected from a vertically integrated water column using either a peristatic pump or an INFILTREX 300 pump system. The INFILTREX 300 pump system is used for the collection of samples of trace levels of organic impurities from large volumes of water. The process is accomplished by pumping the sample water through an XAD-2 extraction column used to concentrate trace organic contaminants. Glass fiber filters (0.5 micrometer [um]) were used to filter out the particulate fraction of the water. Given that hydrophobic analytes are preferentially bound to particulates, this material was isolated in the filter to determine the particulate-bound fraction of hydrophobic analytes present. At the analytical laboratory, the column (“C”) and filters (“F”) were analyzed individually to determine, respectively, the apparent dissolved and particulate concentrations of analytes in the samples. These analytical results were combined to determine the total analyte concentration (“C+F”) in surface water.

Focused COC Concentrations

SampleIDSample Matrix7 Note

pg/LTotal PCBs1 Total PAH2 Total DDx3

ng/L10A

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0.0064A

October 31, 2019 Via E-Mail Sean Sheldrake U.S. ...

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