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Seattle City Light power disruption leads to emergency bypass at West Point, systems restored quickly

Summary

A Seattle City Light power outage that affected more than 10,000 customers caused a brief emergency bypass of stormwater mixed with wastewater from the West Point Treatment Plant in the early morning hours of Friday morning, July 19.

Story

UPDATE:
The bypass prompted the County to close North and South Beaches at Discovery Park as a precaution for the weekend pending water testing results.  All water sample tests taken in the area came back well under the State’s threshold for beach advisories, and the beaches were reopened by Monday July 22. At no time was public health or safety at risk.


A Seattle City Light power surge and outage that affected more than 10,000 customers in Seattle led to a brief emergency bypass at the West Point Treatment Plant early Friday morning, July 19.

The power disruption caused pumping throughout the wastewater treatment plant to shut down. Workers acted swiftly to prevent flooding in the plant by sending an estimated 2.1 million gallons of stormwater mixed with wastewater into Puget Sound through an emergency outfall pipe for 27 minutes, and normal operations were quickly restored.

King County has replaced equipment, updated control systems and increased training of plant operators as a result of the West Point flooding that occurred February 2017. This investment paid off during the night as similar conditions to 2017 occurred and crews prevented flooding and restored the plant to full operations in 27 minutes.

According to an analysis from Seattle City Light, 55 percent of the disruptions at West Point over the last 17 years were caused by malfunctioning electrical facilities. King County has raised concerns about power reliability. A 2017 letter from Department of Natural Resources and Parks to Seattle City Light identified 104 power failures to West Point from 2001 to 2017.

King County employees were in the field Friday morning to collect water samples and post signs in the vicinity of the outfall pipe. The emergency bypass has been reported to health and regulatory agencies.

RELEVANT LINKS

FOR MORE INFORMATION, CONTACT:

  • Doug Williams, 206-477-4543

About the King County Wastewater Treatment Division
King County’s Wastewater Treatment Division protects public health and enhances the environment by collecting and treating wastewater while recycling valuable resources for the Puget Sound region. The division provides wastewater treatment services to 17 cities, 17 local sewer districts and more than 1.7 million residents across a 420-square-mile area in King, Snohomish and Pierce counties.