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Foss Waterway Sediment Cap Repair

In summer 2025, the City of Tacoma’s Environmental Services Department will repair two areas of the sediment cap in the Thea Foss and Wheeler-Osgood Waterways (referred to as RA 3 and RA 8) that are showing signs of erosion. These repairs will help contain remaining contaminants, prevent sediment movement, protect groundwater quality, and support aquatic habitat.
Tacoma

Contact

Seth Gottlieb                                      Construction Project Manager           (253) 370-1983       sgottlieb@tacoma.gov

Laura Nokes                              Engineering Project Manager              (253) 502-2274           lnokes@tacoma.gov

 

Project Description 

This work is part of the City’s long-term commitment to protecting and maintaining these revitalized waterways. Once heavily industrialized and contaminated, the Thea Foss and Wheeler-Osgood Waterways were transformed through a $105 million Superfund cleanup that was completed in 2006. In partnership with state and federal agencies, property owners, and other stakeholders, more than 425,000 cubic yards of polluted sediment was removed or capped, restoring these areas into environmental and recreational assets for the community. 

Project Goals and Outcomes 

These necessary repairs will: 

  • Ensure remaining contaminated sediments remain contained 
  • Prevent sediment erosion and movement to other areas of the waterway 
  • Reduce contaminant transport through groundwater 
  • Provide habitat for aquatic life 

Timeline and Project Milestones 

  • Final Design and Permitting – Spring 2025 
  • Construction Start – Summer 2025 
  • Project Completion – Late Summer / Early Fall 2025 

Funding and Budget 

The sediment cap repair project is estimated to cost approximately $1.14 million. The work is funded by the City’s Stormwater utility fees.