King County's sewer utility crews are working to clean up a wastewater overflow at the North Creek Pump Station in Bothell that was caused by Monday's torrential rainstorm.
When wastewater was diverted to the pump station via the West force main to provide capacity at the West Point Treatment Plant during extremely high flows Monday night, a valve failure at the pump station allowed the highly diluted wastewater to leak for roughly 16 hours before the problem was identified.
It is estimated that 500,000 gallons or more leaked. Much of the wastewater flowed to a containment pond, which drains into the Sammamish River. To protect public health, the area was posted and a clean-up plan put into place.
The remaining material will be cleaned up as conditions allow. The saturated ground is currently too soft to accommodate a vactor truck. Crews have pumped out residual wastewater and have done physical clean-up where soil conditions have allowed trucks.
King County Environmental Laboratory staff took water samples at the water body, and public health and regulatory agencies were notified.
People enjoy clean water and a healthy environment because of King County's wastewater treatment program. The county's Wastewater Treatment Division protects public health and water quality by serving 17 cities, 17 local sewer utilities and more than 1.4 million residents in King, Snohomish and Pierce counties. Formerly called Metro, the regional clean-water agency now operated by King County has been preventing water pollution for more than 40 years.