Murray CSO control project -- Building a new storage tank to protect Puget Sound
November 17, 2014 Update
King County contractors finished digging out the tank area at the Murray CSO Control Project site on Thursday, November 13. The resulting hole is 60 feet deep – big enough to house the facility’s one million gallon underground storage tank. The tank will help keep sewage and stormwater out of Puget Sound.
Before the tank can be built, crews must install a 17-foot thick concrete base below the tank. The base will keep the tank from being pushed out of the ground by groundwater. Rebar will be installed in the next 10 days. Then nearly 5,000 cubic yards of concrete will be poured into the hole over three days to build the base.
Learn more: view the construction update (PDF, November 17, 2014).
Have a comment or question? Need more information about the project?
Click here to contact the project team.
Murray Project Hotline: 206-205-9186
Final Design, December 2012
Project haul routes, February 2014
Murray basin and project location
King County is designing an underground storage tank across the street from Seattle’s Lowman Beach Park. The tank will store approximately one million gallons when the Murray Pump Station exceeds maximum capacity.
Why do we need this project?
Protect public health
Like many cities around the country (external link), the older parts of King County's wastewater system uses a single set of pipes to carry untreated sewage and stormwater to a treatment plant. To prevent sewer backups into homes and streets, the system includes safety valves called “combined sewer overflows” that route excess sewage and polluted stormwater flow directly into Puget Sound during storms. Although CSOs reduce potential exposure to untreated sewage, they pose significant public health concerns.
Clean up Puget Sound
The Murray CSO control facility will reduce CSOs into Puget Sound. State regulations require no more than one untreated discharge per year. The Murray Pump Station averages five untreated CSO events per year, discharging 5 million gallons into Puget Sound off of Lowman Beach Park.
View construction schedule overview (PDF) and project meeting calendar.
How has the community shaped facility design?
Since October 2011 Lowman Beach Park neighbors and park users have worked with local designers, environmentalists and community advocates to help the King County project team design a facility that fits with the community. These discussions produced “common themes” for the design that reflect the community’s values for a safe, reliable facility. The common themes are:
- Minimize the “industrial facility” feel
- Encourage views of Puget Sound
- Discourage through traffic on Beach Drive
- Enhance continuous space between Lowman Beach park and the facility site