Toxic pilings pulled from the Duwamish

By Daily Journal Of Commerce/Journal Staff Aug 19, 2022

Crews from Pacific Pile & Marine are busy pulling 1,800 timber pilings coated in toxic creosote from the mouth of the Duwamish River in Seattle.

King County’s Solid Waste Division is leading the $8.1 million project, which also removed a 72,700-square-foot derelict dock along the Harbor Island shoreline that was supported by the pilings.

“Improving water quality where the river meets Elliott Bay builds on the progress we are making upstream to revitalize the Green-Duwamish Watershed for people, fish, and wildlife,” said King County Executive Dow Constantine in a news release. “Removing nearly 2,000 contaminated creosote timber pilings from the Duwamish River will produce immediate and lasting benefits for marine life.”

In the past, creosote was used to preserve wood in wet environments. It is harmful to water quality and marine life.

Pacific Pile & Marine used heavy machinery aboard a barge to pull most of the pilings from the riverbed for safe disposal off site. Broken pilings that could not be extracted will be cut off and removed with the help of divers excavating around the pilings.

After completing in-water work, crews will remove the concrete bulkhead and other dock components on land and stabilize the shoreline. Crews will also install an environmental cap of clean gravel on top of the areas where the pilings were seated in the riverbed.

All work should be finished by the end of next month.

King County says it coordinated with local, state and federal agencies to reduce impacts on water quality and the surrounding environment throughout the project. It also worked with tribes to minimize potential effects on local salmon, including pausing construction during tribal salmon fisheries.

KPFF Consulting Engineers is also on the project team.