Cleanup of Thea Foss Waterway begins

Major environmental cleanup of the Thea Foss and Wheeler-Osgood waterways is under way. City of Tacoma contractors are in the water, preparing to remove more than a century of pollution, after 20 years of testing, legal negotiations, design work and coordination among about 100 private businesses and local, state and federal agencies.

The City of Tacoma, during the next two to three years, plans to dredge 525,000 cubic yards of contaminated sediment – enough to fill 38.5 Museum of Glass cones – from the Thea Foss and Wheeler-Osgood waterways.
Cleanup plans call for the city to lead work in 80 percent of the Thea Foss Waterway – an area extending from near the State Route 509 Bridge to the mouth of the waterway. This area also includes the small Wheeler-Osgood Waterway, just south of the Murray Morgan Bridge at 11th Street.

The bulk of the dredging will begin next year, but this year’s first major in-water work involves removing pilings in front of Albers Mill and other locations and dismantling a portion of the Foss Landing Marina (the old Pick’s Cove) in the Thea Foss Waterway to get ready for dredging.

Activities scheduled for later this fall include building new marinas at Albers Mill and in front of the Museum of Glass to hold boats moved temporarily during dredging; the marinas will remain after the cleanup as permanent enhancements to the waterway.

Much of the contaminated sediment will be dredged hydraulically through a pipeline to a disposal site in the St. Paul Waterway, near Simpson Company, where it will be capped to confine the contaminants.

Disposal site preparations include pulling pilings, demolishing an old building, relocating the log haulout structure, modifying the existing fuel dock and installing a pipeline to carry sediments to the disposal site.

Upon completion of capping, part of the disposal site will become available to Simpson as buildable land; the other part is planned as a marine habitat.
The city’s bill for this major portion of the waterway cleanup is estimated at $50 million. The city has received $12 million from about 70 other companies and agencies responsible for the contamination. These organizations have chosen to “cash out” rather than participate in the cleanup process. Surface water rates, bonds, reserves and grants will round out the remaining $38 million.

The contractor selected for the project, Manson Construction Co. of Seattle, may work in the water only from Aug. 15 to Feb.15 to comply with what is typically called the “fish window.” During six months in the spring and summer, the National Marine Fisheries Service prohibits in-water work to protect salmon and other migratory fish. The city chose KPFF Consulting Engineers of Seattle to manage construction of the project.

Scheduled to begin today, alongside the city’s work, a group of private companies will clean up the other 20 percent of the Thea Foss, an area extending from just north of the SR 509 Bridge to the end of the waterway.

Their work, at a cost of about $8 million, will include removing debris, cutting off pilings, dredging an estimated 7,500 cubic yards of contaminated sediments, capping the area and installing an underwater, retaining wall across the waterway. The construction contractor for the project, Wilder Construction, based in Everett, plans to complete work by the Feb. 15 migratory fish window.

The Environmental Protection Agency (EPA) placed the historic Thea Foss and Wheeler-Osgood waterways on its Superfund list in 1983 as part of the larger Commencement Bay site.

The city completed earlier cleanup work in February at six sites along the Thea Foss and part of the Wheeler-Osgood waterways, including removing old pilings, capping some of the less-contaminated sediment with several feet of clean sand, installing a sheet-pile bulkhead and restoring wildlife habitat along the banks.

This early work, along with previous sampling, testing, analysis, arbitration, design work and EPA oversight and approvals, has cost the city $24 million since 1994. That’s when the city voluntarily took the lead to develop a plan to clean up the polluted sediments after more than a decade of legal wrangling among hundreds of entities.

For more information about the cleanup, call the 24-hour Foss Cleanup Hotline at 253/233-1995 or visit