History of sediment management program

King County (and former Metro) recognized early on that toxics found in wastewater were finding ways into local waterbodies. Historical discharges of wastewater that were untreated or poorly treated had caused a buildup of toxics in some areas of waterbodies as well. As these toxics have been reduced in wastewater through source control measures and a reduction in CSO discharges, their continued presence in the waterways was an issue needing to be addressed. With the passing of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) in the 1980s, known as Superfund, the US EPA began to clean up highly polluted upland areas. In the late 1980s voters in the state of Washington passed the Model Toxics Control Act (MTCA) providing a similar program ran at the state level. As part of MTCA, sediment management standards were set to guide cleanup of contaminated sediments.

• 1990 to present
• Pre-1990