Program -- History of local sediment cleanup

1990 – Metro performed a voluntary sediment capping project at Denny Way CSO as a demonstration project and interim solution for improving sediment quality in Elliott Bay .

1990 – Damage Assessment and Restoration Program (NOAA) - NOAA's Damage Assessment and Restoration Program was established to fulfill natural resource trustee responsibilities assigned in the Clean Water Act, CERCLA, Superfund Act, Oil Pollution Act of 1990, and National Marine Sanctuaries Act.

1991 – The state Department of Ecology adopted sediment management standards for designating marine sediments that have adverse effects on aquatic animals and requiring cleanup of those sediments. Washington is one of the first states to have such standards.

1991-1992 – Metro facilitated interagency meetings and funded a report which prioritized the risks due to contaminated sediments in Elliott Bay and the Duwamish Waterway. The report identified the Pier 53-55 area as a high priority for site cleanup.

1991 – King County and the City of Seattle reached an agreement with the National Oceanic and Atmospheric Administration (NOAA) Damage Assessment and Restoration Program to fund sediment cleanup projects, habitat restoration and source control in Elliott Bay and the Duwamish Waterway. King County, NOAA and the City of Seattle formed a program with other natural resource trustees called the Elliot Bay Duwamish Restoration Program (external link). Other members include the U.S. Fish and Wildlife Service, Muckleshoot Indian Tribe, Suquamish Tribe, and Ecology.

1991-1994 – The Puget Sound Water Quality Management Plan is updated establishing an ambient monitoring program for contaminated sediments.

1993 – A three foot cap was placed on sediments near Pier 53-55 in Elliot Bay. Sediments were contaminated by an historical sewer outfall in that area.

1995 – King County (formerly Metro) began implementing the CSO Sediment Baseline Monitoring Plan, developed as a condition of its NPDES permits, that provides for the monitoring of marine sediments in the vicinity of wastewater treatment plant outfalls and CSOs.

1996 – Based on existing information, Ecology identified 49 sites in Puget Sound that did not meet sediment management standards. Of the 49 sites, 19 are in Elliott Bay/Duwamish Waterway. Seven of the 19 sites are near King County combined sewer overflows (CSOs):

• Hanford Street CSO (Elliott Bay)
• Lander Street CSO (Elliott Bay)
• Duwamish/Diagonal CSO/storm drain (Duwamish Waterway)
• Brandon Street CSO (Duwamish Waterway)
• King Street CSO (Elliott Bay)
• Denny Way CSO (Ellliott Bay)
• Chelan Avenue CSO (Duwamish Waterway)

1999 – King County developed a plan to address the seven sites near King County CSOs. The Sediment Management Plan laid out a schedule to voluntarily remediate the sites.

1999 – The Norfolk Combined Sewer Overflow (CSO) cleanup project removed contaminated sediments from the Duwamish Waterway to enhance and restore the river habitat.

2000 – King County-along with the City of Seattle, Port of Seattle, and the Boeing Co.-has formed the Lower Duwamish Waterway Group (external link) to address sediment contamination in the lower Duwamish Waterway. The LDWG partners signed a voluntary agreement to investigate sediments in the Lower Duwamish Waterway. Their goal: an ultimate plan to clean up Duwamish sediments contaminated by local industries and cities during the first half of the 20th century.

In 2001, the EPA placed the Lower Duwamish Waterway (external link) on its Superfund list. That launched a formal process that will lead to cleanup of more contaminated sediments throughout the Duwamish Waterway. Under the Superfund process, EPA and Ecology are overseeing a remedial investigation/feasibility study that the LDWG partners are conducting.

2004 – The Duwamish/Diagonal Sediment Remediation Project project isolated contaminated sediment near four outfall pipes on the Duwamish Waterway in Seattle