Holiday closure Monday May 28: Most county offices will be closed in observance of Memorial Day.
For questions about the Duwamish Waterway Programs, please contact Doug Marsano. 

Wastewater Treatment Division
King Street Center
201 S. Jackson St., Suite 505
Seattle, WA 98104-3855

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The Duwamish Waterway... running towards a brighter future

Cleaning up the Lower Duwamish

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Principles of an effective cleanup

King County believes that an effective cleanup must:

  • Address the most contaminated areas in the first years of the cleanup to achieve the greatest risk reduction as soon as possible.
  • Be implemented in phased actions to allow for adjustments based on further sediment quality assessments, risk assessments and the effectiveness of source control measures.
  • Minimize environmental impacts while achieving long-term protection.
  • Meet all cleanup goals as cost-effectively as possible.
  • Reflect lessons from other cleanups, especially those highlighted by independent, scientific peer reviews.