Short-term beach and trail closure Sept. 7-8 at Discovery Park when King County’s West Point Treatment Plant replaces pipe

August 30, 2022

Summary

To protect public health and safety, King County construction work at the West Point Treatment Plant will require a short-term closure of access to North and South beaches, the lighthouse, and the nearby beachfront parking lot area in Discovery Park, Sept. 7-8.

Story

North and South Beaches, the lighthouse, and the nearby parking lots of Discovery Park will be briefly closed Sept. 7-8 as King County replaces a critical pipe at the West Point Treatment Plant.  

Crews will replace a pipe that carries biogas from the plant’s digesters to its cogeneration system, which uses the gas to generate electricity. The pipe to be replaced is at the end of its life. Replacing it requires a planned release of biogas, which will emit a sulfur or rotten egg-like smell noticeable to those near the plant.  

To limit impacts to park users and neighbors, the pipe replacement will begin at 3 a.m. on Wednesday, Sept. 7, and continue until the new pipe is installed and operational. King County anticipates work will be completed on Thursday, Sept. 8, and will re-open closed areas of Discovery Park as soon as it is safe to do so.  

While the work area is within the boundaries of the treatment plant, temporary odors from the released biogas could impact nearby areas. By closing access to nearby trails, beaches and parking lots, King County is reducing the likelihood that a park visitor would encounter the odor.  

Park visitors should avoid areas likely to be impacted by the biogas release. Park users who notice a strong rotten eggs smell should return from the direction that they came until they no longer detect the odor.  

King County is working with Seattle Parks and Recreation and local police and fire departments to keep people a safe distance from areas that could be impacted. There will be closure signs at beaches, trails leading to the beaches, in the North, South, and East parking lots, and in other high-traffic areas. The beach closure will be enforced by a uniformed officer from the Seattle Police Department.  
 
King County will monitor air quality throughout the duration of the work. 
 
In 2011, King County installed West Point’s cogeneration system, which converts gas from the sewage treatment process into a source of heat and energy for the plant. Along with providing heat for the West Point Treatment Plant, some of the gas is converted to electricity and sold to Seattle City Light. West Point’s cogeneration system produces about 23,000 Megawatt-hours of electricity each year – enough electricity to power more than 2,000 homes.

Relevant links 

• West Point Treatment Plant 

For more information, contact:  
Marie Fiore, Wastewater Treatment Division, 206-263-0284