Extensive power outages push regional wastewater system to its capacity and onto back up power: overflows into Puget Sound and Lake Washington from West Point, Richmond Beach and Medina pump stations

January 13, 2021

Summary

Power outages throughout the service area caused overflows at King County Wastewater Treatment Division’s West Point Treatment Plant, and Richmond Beach and Medina pump stations.

Story

King County reported stormwater and sewer overflows into Puget Sound from West Point Treatment Plant and Richmond Beach pump station and into Lake Washington from the Medina pump stations occurred early in the morning on Wednesday, Jan. 13, as a result of widespread power outages.

Between midnight and 2 a.m., West Point experienced a series of voltage fluctuations causing in-plant pumping stations to shut down repeatedly. While county field operators worked to get the pumps running consistently, operators were able to mitigate the amount of the overflow by controlling the partial closing of the emergency bypass gate. Equipment and operations worked as needed to protect the plant and employee safety from flooding. All systems were back online within 2 hours.
 
The emergency caused an estimated 11 million gallons to overflow without treatment into Puget Sound.  Approximately 80% was stormwater and 20% was sewage.  Large volumes of rainfall throughout the day and into the night exceeded the capacity of the Richmond Beach pump station, and the volume of flow through the Medina Pump Station overwhelmed the station as it transitioned from line power to generator power and back to utility power. These two stations overflowed estimated volumes of 165,000 and 80,600 gallons respectively.

 King County operates 48 pump stations and 25 regulator stations. Crews worked throughout the night to make sure they operated without incident. A total of 17 pump stations had to run on generator power throughout the storm before returning to utility power.

King County has notified health and regulatory agencies, will test water quality and has posted beach closure signs at Discovery Park (nearest West Point), Carkeek, Golden Gardens, Richmond and Medina Park beaches warning people to avoid contact with the water over the next several days as a precaution to protect public health.

Updates will be posted in the DNRP Newsroom.

FOR MORE INFORMATION, CONTACT:
Marie Fiore, 206-263-0284 or mfiore@kingcounty.gov

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 1.8 million residents across a 420-square-mile area in King, Snohomish and Pierce counties.

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