Dredge Material Sediment Sampling, Characterization and Reuse/Disposal Reporting and Consultation Services - Crescent City Harbor Federal Channels

Client: U.S. Army Corps of Engineers, San Francisco District (USACE)

Location: Crescent City Harbor Federal Channels

Period of Performance: May - December 2009

Project Overview: Crescent City Harbor is a shallow-draft critical harbor of refuge, supporting a Coast Guard search and rescue station, commercial and sport fishing, waterfront industry and recreational boating. There are three connecting federally constructed and maintained navigation channels within the harbor which are comprised of the Entrance Channel, the Inner Harbor Basin Channel, and the Marina Access Channel. The USACE proposed to dredge the Crescent City Harbor Federal Channels as a part of its Operations and Maintenance Dredging Program.

Scope of Services: Based upon the USACE's Crescent City Harbor FY 2009 Maintenance Dredging Sampling and Analysis Plan (SAP) for Federal Channels and the Sediment Evaluation Framework (SEF) for the Pacific Northwest, ADH developed and managed all technical aspects of this 8(a) sole-sourced, Firm Fixed-Price contract including contracting with research vessel operators, vibracoring subcontractor, and National Environmental Laboratory Accredited Program (NELAP) certified analytical and toxicological laboratories who could meet USACE required ultra low method detection limits for dioxins and PCBs. ADH staff, in association with our vessel and vibracoring subcontractors, performed all sediment coring and site water sampling from three navigational channel composite areas and one offshore reference site in accordance with the SAP. The sediment composite samples were subjected to Tier III Testing - a comprehensive suite of physical and chemical analyses, biological toxicity and bioaccumulation tests. Analytical physical, chemical and toxicological methods followed procedures specified in the Inland Testing Manual, the Ocean Testing Manual and the Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms.

Results of physical and chemical sediment analyses, modified elutriate tests, benthic and water column toxicity tests, bioaccumulation tests and tissue bioaccumulation analyses were evaluated to determine the harbor sediment's suitability for potential placement at four different disposal locations: an upland disposal site owned by the Crescent City Harbor District, a beach nourishment site located on Whaler Island, the Humboldt Open Ocean Dredged Site, and the Chetco ocean disposal site located in Oregon. Sediment chemistry analyses and toxicity testing results were evaluated in relation to criteria established in the above referenced documents, the SEF, the California Toxics Rule and the USEPA's Section 304(a) criteria for Priority Toxic Pollutants. Water column toxicity Limiting Permissible Concentrations were also calculated using the ADDAMS model. The report followed guidelines provided in the SAP and Public Notice 99-4: Sampling and Analysis Plan (Quality Assurance Project Plan) Guidance for Dredging Projects within the San Francisco District.

The project was overseen by the USACE and the final report incorporated comments from the Dredged Material Management Office (comprised of USEPA Region 9, San Francisco Bay RWQCB, Bay Conservation and Development Commission, and California Department of Fish & Game), NOAA Fisheries, U.S. Fish & Wildlife Service, California Coastal Commission, Oregon Department of Land Conservation and Development, and Oregon Department of Environmental Quality.