Elliott Bay/Duwamish Restoration Program
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FINAL Duwamish/Diagonal CSO/SD Cleanup Study Report Elliott Bay/Duwamish Restoration Program Prepared for the Elliott Bay/Duwamish Restoration Program Panel by King County Department of Natural Resources and Parks Anchor Environmental, L.L.C. EcoChem, Inc. Panel Publication 30 Elliot Bay/Duwamish Restoration Program NOAA Damage Assessment and Restoration Center Northwest 7600 Sand Point Way NE Seattle, WA 98115-0070 (206) 526-6029 FAX (206) 526-6665 October 2005 Individuals and organizations needing further information about the Elliot Bay/Duwamish Restoration Program should contact the Administrative Director at the following address and telephone number: John Kern, Administrative Director Elliot Bay/Duwamish Restoration Program NOAA Damage Assessment and Restoration Center Northwest 7600 Sand Point Way NE Seattle, WA 98115-0070 (206) 526-6029 FAX: (206) 526-6665 The Panel of Managers holds regularly scheduled meetings that are open to the public. Technical Working Group and committee meetings are scheduled on an as-needed basis, and are also open to the public. Meetings are generally held at the National Oceanic and Atmospheric Administration, National Marine Fisheries Service – Regional Directorate Conference Room, Building 1, 7600 Sand Point Way NE, Seattle. The Panel recommends that you contact the Administrative Director at the above phone number to confirm meeting schedules and locations. The panel also holds periodic special evening and weekend public information meetings and workshops. General Schedule for Panel and Committee Meeting Dates Panel: quarterly, first Thursday of January, April, July, and October, 9:30 A.M. – 12:30 P.M. Habitat Development Technical Working Group: third Thursday of every month, 9:30 A.M. – 12:30 P.M. Sediment Remediation Technical Working Group: scheduled as needed. Public Participation Committee: scheduled as needed. Budget Committee: scheduled as needed. Environmental Review of Specific Products Formal hearings and comment periods on appropriate environmental documents for proposed sediment remediation and habitat development projects will be observed. Please contact the Administrative Director for more information. This information is available in accessible formats on request at (206) 296-0600 (voice) and 1-800-833-6388 (TTY/TDD users only). TABLE OF CONTENTS EXECUTIVE SUMMARY...................................................................................................................................ES-1 1.0 INTRODUCTION ............................................................................................................................................1-1 1.1 PROJECT OVERVIEW.....................................................................................................................................1-1 1.2 REPORT ORGANIZATION .............................................................................................................................1-2 2.0 SITE DESCRIPTION .......................................................................................................................................2-1 2.1. PROJECT LOCATION.....................................................................................................................................2-1 2.2. ADJACENT LAND USE AND PROPERTY DESCRIPTIONS ..............................................................................2-1 2.3. SHORELINE FEATURES AND BATHYMETRY.................................................................................................2-1 2.3.1. Navigation...............................................................................................................................................2-5 2.4. WATER RESOURCES .....................................................................................................................................2-5 2.4.1. Duwamish River.....................................................................................................................................2-5 2.4.2. Surface Water Drainage and CSOs ........................................................................................................2-6 2.4.3. Groundwater Drainage...........................................................................................................................2-8 2.5. ECOLOGICAL RESOURCES............................................................................................................................2-8 2.5.1. Habitat.....................................................................................................................................................2-8 2.5.2. Fish and Wildlife .....................................................................................................................................2-9 2.5.3. Beneficial Uses.......................................................................................................................................2-12 3.0 SOURCE CONTROL EVALUATION ..........................................................................................................3-1 3.1 COMBINED SEWER SYSTEM OVERVIEW........................................................................................................3-1 3.2 POTENTIAL CONTAMINANT SOURCES ........................................................................................................3-2 3.2.1 Diagonal Stormwater and CSO Outfall .................................................................................................3-2 3.2.2 Duwamish CSO Outfall..........................................................................................................................3-3 3.2.3 Diagonal Avenue South Storm Drain.....................................................................................................3-4 3.2.4 Former City Treatment Plant Outfall.....................................................................................................3-5 3.2.5 Other Potential Sources ..........................................................................................................................3-6 3.2.6 Surface Water Runoff..............................................................................................................................3-6 3.2.7 Groundwater ...........................................................................................................................................3-7 3.3 STRUCTURAL IMPROVEMENTS AND WATERSHED SOURCE CONTROLS.....................................................3-8 3.3.1 Duwamish CSO Outfall..........................................................................................................................3-8 3.3.2 Diagonal SD/CSO Outfall......................................................................................................................3-8 3.4 RECONTAMINATION MODELING RESULTS .................................................................................................3-9 3.4.1 METSED Model - KCDNR..................................................................................................................3-10 3.4.2 Mass Balance Model - By WEST Consultants .....................................................................................3-11 3.4.3 Factors Supporting Remediation...........................................................................................................3-12 Final Cleanup Study Report Page i Duwamish/Diagonal CSO/SD October 2005 4.0 DATA COLLECTION AND RESULTS ...............................................................................................4-1 4.1 STUDY OBJECTIVES ......................................................................................................................................4-1 4.2 FIELD AND LABORATORY METHODS..........................................................................................................4-1 4.2.1 Field Methods..........................................................................................................................................4-2 4.2.2 Laboratory Methods ................................................................................................................................4-5 4.3 QUALITY ASSURANCE / QUALITY CONTROL RESULTS ...............................................................................4-7 4.3.1 QA Review of Phase 1 Data ....................................................................................................................4-8 4.3.2 QA Review of Phase 1.5 Data ...............................................................................................................4-10 4.3.3 QA Review of Phase 2 Surface Sediment Data .....................................................................................4-10 4.3.4 QA Review of Phase 2 Subsurface Data................................................................................................4-11 4.3.5 QA Review of Phase 2 Bioassay Data ...................................................................................................4-13 4.4 SURFACE SEDIMENT CHEMISTRY RESULTS ...............................................................................................4-14 4.4.1 Conventionals........................................................................................................................................4-15 4.4.2 Inorganics..............................................................................................................................................4-16 4.4.3 Organics................................................................................................................................................4-16