By Mark Daniel
While The Watershed Company might often be thought of as in the business of daylighting streams, in a recent project we helped daylight sedimentation tanks!
The West Point Treatment Plant, located in Seattle’s Discovery Park, is a crucial piece of the region’s infrastructure—the plant serves upwards of 700,000 people.
The plant was originally constructed in the mid-60s, including the primary treatment facility.
West Point Treatment Plant under construction, 1965 (Photo credit: King County Wastewater Treatment Division)
The primary treatment facility was built with a massive concrete roof—the completed roof had nearly 600 beams, with each beam weighing about 10,000 pounds!
West Point Treatment Plant, 2006 (Photo credit: Washington State Department of Ecology)
A seismic evaluation determined that the primary treatment facility did not meet minimum seismic safety standards. In response, King County, in collaboration with a consultant team led by Reid Middleton engineers, considered several options for improving the seismic resiliency of the facility. The County ultimately decided that the best approach was essentially to remove the roof. The Watershed Company supported the project with environmental and permitting assistance.
Demolition and construction work is currently under way and much of the roof has already been removed. Project completion is anticipated in 2023.
Primary treatment facility during roof removal, 2021 (Photo credit: Stellar J)
