TagDuwamish River(24)

A April 14, 1999 email from Mike O'Neil of Metro King County discusses plans to use a Port of Seattle runway at Sea-Tac Airport as a disposal site for dredged material from Turning Basin #3 on the Duwamish/Hamm Creek project. The Port's contact, John Rothnie, found the material geotechnically and environmentally acceptable, but noted that sending more than 6 trucks per hour could trigger a special permit requirement from the City of SeaTac. Hauling was estimated to begin in June 1999 and conclude in August, with contingency plans for dewatering especially wet material at an alternative commercial site.

This 1997 report by Science Applications International Corporation characterizes sediment quality in the Duwamish Turning Basin near Seattle, Washington, as part of the Hamm Creek Restoration Project. It presents results from chemical testing, biological bioassays, and sediment sampling to evaluate contaminant levels and compare them against sediment management standards. The study was prepared for the U.S. Army Corps of Engineers, Seattle District.

Draft amendments prepared by Tom Culhane and Jerry Liszak of Washington Department of Ecology Northwest Regional Office, Water Resources Program, replacing text of OFTR 95-01 for the Initial Watershed Assessment of Water Resources Inventory Area 9 (WRIA 9), Green-Duwamish Watershed. Document covers hydrogeology, ground water-surface water interaction, water demand, streamflow status, water rights and claims

A 1990 environmental assessment by Roy F. Weston Inc. evaluated soil and groundwater quality on an undeveloped Seattle property along the Duwamish Waterway, where Boeing was considering a 50-year lease with Seattle City Light. The study examined areas where dredged sediment from the Duwamish Waterway had been deposited in 1968 and 1985, testing for contaminants including PCBs, pentachlorophenols, PAHs, and metals. Prior sampling had found contaminant levels generally below state-regulated thresholds, and this baseline assessment was conducted to document existing conditions before any lease agreement was finalized.