Water infrastructure projects like the Portland CSO Program and DC Water’s CSO Program benefitted from tunnel solutions that garnered widespread public support.
The Portland tunnel project involved the construction of 10 miles of tunnel on both sides of the Willamette River to collect, store and transport overflows to a pump station to be treated before returning to the river, as part of the city’s Clean River Program. WSP served as lead designer for both the East Side and West Side tunnels that traversed sensitive neighborhoods in downtown Portland.
WSP also provided construction and inspection management for the DC Water tunnel project, part of the Clean Rivers Program to reduce pollution in the Potomac River and its tributaries. The project included the 5-mile-long, 23-foot diameter Blue Plains Tunnel that mitigates discharges into Washington, D.C. rivers that are harmful to wildlife and the public.
WSP was also the designer for the First Street Tunnel in Washington, D.C. which provided the city’s northern neighborhoods with a sewage and storm water system to handle severe flooding conditions that once plagued the area.
Today, in California’s East Bay region, WSP is supporting the East Bay Municipal Utility District (EBMUD) on the Mokelumne Aqueducts Delta Tunnel project, a 16.5-mile-long, 15- to 20-foot diameter tunnel, that connects to an aqueduct which that provides the primary water supply for 1.4 million people living in an area that includes Oakland. The tunnel crosses the Mokelumne River Delta from east to west, beginning in Stockton and ending in Bixler.
WSP is providing project management and is leading a seismic analysis of the existing aqueducts, an alternatives analysis, tunnel conceptual design and cost estimating.
“The existing aqueducts – three pile-supported pipelines – are considered vulnerable and could fail during a large seismic or flooding event,” said Ken Johnson, WSP project manager for the Mokelumne Aqueducts Delta Tunnel. “A tunnel constructed beneath the unstable surficial soils will provide a more reliable water conveyance system for the District’s customers.”
Work on the project began in March 2020 and the initial planning and conceptual engineering will be completed in 2022.
“It is very rewarding to work on a project of this magnitude that is so important to so many people, including our friends and relatives many of whom are EBMUD customers,” Johnson said.