Seattle’s Discovery Park North and South Beaches will close Wednesday and Thursday due to construction at the West Point processing plant.
The West Point Lighthouse, beach side parking lot, nearby trails and road access to the area will also be closed as crews begin replacing a pipe that serves a critical purpose for the plant.
The pipe, almost 30 years old, is at the end of its life and must be replaced. The replacement process will release biogas — emitting a sulfur or rotten egg smell to the area, but visitors won’t be able to smell it, said Marie Fiore, spokeswoman for the county’s sewage treatment division. King.
“The contractor is going to have a temporary waste gas burner on site,” Fiore said. “So we’re actually going to burn the gas instead of venting it directly into the atmosphere.”
If park users notice a strong smell, they are advised to turn back until they no longer detect the smell. The beach closure will be enforced by the Seattle Police Department.
Construction is expected to begin Wednesday at 3 a.m. and last through Thursday. Crew members will monitor any impact on air quality.
The 56-year-old West Point treatment plant is part of a regional water treatment system and treats wastewater from Seattle, Shoreline, northern Lake Washington, northern parts of King County and from parts of southern Snohomish County.
The plant treats approximately 90 million gallons of wastewater per day in the summer. During rainy months, the plant processes up to 300 million gallons per day, up to 80% of which may be stormwater. Excess water brought in by rain and storms can put a strain on the sewage system.
In February 2017, sewage overflowed from West Point, causing catastrophic flooding at the sewage treatment plant. The plant ended up dumping about 235 million gallons of untreated sewage into Puget Sound. The Washington Department of Ecology fined King County $361,000 for mismanagement that led to the incident.
In January 2021, the West Point plant and four other regional plants spilled more than 10 million gallons of untreated sewage into Puget Sound after being hit by heavy rainfall and a power outage at the same time, according to the Bothell-Kenmore Reporter. About two million gallons of raw sewage was sewage.
In response, King County officials took out a $96.8 million loan from the U.S. Environmental Protection Agency to design and build an underground storage tunnel that could hold millions of gallons of water. excess stormwater to relieve pressure on the sewage system, including the West Point plant.