Duwamish River - Modern Use

Modern Use

The Duwamish Waterway empties into Elliott Bay in Seattle, divided by the man-made Harbor Island into two channels, the East and West Waterways.

Due to 20th century industrial contamination, the lower 5 miles (8.0 km) of the Duwamish was declared a Superfund site by the United States Environmental Protection Agency. The contaminants include PCBs, PAHs, mercury, and phthalates. The cleanup of the river has been controversial: the original plan was to dredge the river and dump the resulting sludge in Tacoma's Commencement Bay, 26 miles (42 km) to the southwest. Local opposition to this plan forced the sludge to be shipped to Klickitat County in south central Washington.

Along with the contaminants already mentioned above the Duwamish River faces other types of pollution as well. One other major form of pollution is fecal coliform caused by sewage overflow. Even if these overflows were to be cleaned up the overall quality of the water would not improve much. Contamination would still occur from farms, surface runoff, wildlife, or failing septic tanks. Also, the Duwamish River's most common pollutant is petroleum.