Posted on January 1, 2024
Dredging two sections of the Duwamish River federal navigation channel will begin Jan. 2, 2024.
Mechanical clamshell dredging operations will remove about 75,000 cubic yards of accumulated sediment from the federal channel’s Turning Basin and Section A, ensuring safe passage for vessels. These sections begin nearly five miles upstream of Harbor Island.
The U.S. Army Corps of Engineers (USACE) manages the federally authorized channel and will place the material at the Elliott Bay open water dredged material disposal site near Seattle, Washington.
Before dredging approval, USACE must comply with the Endangered Species Act and receive a Suitability Determination indicating the material is suitable for an open water disposal site.
The eight-week project will operate 24/7 and officials expect to finish by the designated in-water work window ending Feb. 15, 2024. These restrictions help minimize any potential impacts to out-migrating juvenile salmonids, forage-fish spawning, and to minimize interference with tribal fishing activities.
Dredging machine noise should be minimal but can amplify and travel long distance over water. Boaters should avoid the area during this period, if possible. If not, they should slow down, pass on the marina side of the dredge, pay attention to rig markings and be cautious around the dredging operations.
One of the Seattle District’s primary missions is to maintain the navigation channels and harbors in the Pacific Northwest. Maintenance and navigation dredging are performed frequently in harbor areas, ports, and marinas. A significant component of Washington State’s economy relies on navigation and commerce, which requires dredging state waterways such as the Duwamish River.