Water Quality Assessment and Monitoring Study
The study’s Synthesis Report presents many of the findings from the more detailed documents, including these:
Some long-term water quality trends show improvements – even as our region has grown. Our region’s water quality investments over the last 40 years have paid off.
- Less bacteria that can make people sick.
- Fewer nutrients that can cause toxic algae blooms.
- More dissolved oxygen for fish to breath.
There is more to do to achieve water quality goals.
- Water temperature is getting warmer, which is worse for fish.
- Even with the long-term improvements, water does not always meet state water quality standards for bacteria, dissolved oxygen, temperature or human health standards for banned industrial chemicals called PCBs.
- Historically contaminated sediments need to be cleaned up or contained.
Completing the CSO program will protect water quality.
- By 2030, King County and the City of Seattle are scheduled to finish CSO projects to meet state standards.
- This will reduce the amount of fecal coliform bacteria entering the water bodies by 80 percent.
- It will take more than CSO control to achieve water quality goals
Stormwater runoff and upstream watersheds carry many pollutants to the water bodies.
- Many jurisdictions are developing new stormwater rules and regulations. A regional commitment and investment to address stormwater runoff, similar to wastewater treatment, will be needed.