Rosie, the 530-ton tunnel boring machine that the City of Portland is using for its East Side Big Pipe project has completed its tunneling 4 months ahead of schedule. The tunnel will manage rain runoff and keep combined sewer overflows out of the Willamette River.
Big Pipe project ahead of schedule
Rosie, the 530-ton tunnel boring machine, has finished tunneling on the East Side Big Pipe project. The East Side Big Pipe is part of Portland’s program to control combined sewer overflows, and is the largest public infrastructure project in Portland’s history.
Rosie started working in September 2007. It bored into the McLoughlin shaft on Oct. 18 to complete tunneling about 4 months ahead of schedule. Work is beginning now to prepare the nearly 6-mile long, 22-foot diameter pipe for activation. The tunnel will be ready to accept combined sewage by late next summer.
The $426-million project is the largest sewer construction project in Portland history. Environmental Services is working to complete several other sewer overflow projects including the Balch Consolidation Conduit, the Sellwood Wet Weather Pump Station, the Portsmouth Force Main, and Phase 2 of the Swan Island CSO Pump Station.
When construction is complete in December 2011, Portland’s combined sewers will overflow to the Willamette River an average of once every three summers and four times each winter, instead of every time it rains.
The entire 20-year combined sewer overflows program will cost Portland sewer ratepayers an estimated $1.4 billion.