The River’s Lung

The access shaft to Portland’s Big Pipe, the underground “lung” that has protected the Willamette River since 2006. 1/1

There are infrastructures that reshape the landscape. Others, more quietly, bring it back to life. When Lane completed the Big Pipe beneath the streets of Portland, Oregon, in 2006, few could have imagined how profoundly the project would transform the relationship between the city and the Willamette River.

Today, that massive underground tunnel continues to perform the task it was designed for: capturing stormwater and sewage during heavy rainfall and preventing untreated discharges from reaching the river.

Hidden beneath the city, it works like an enormous lung. It draws in the water the Willamette could no longer absorb and, after treatment, returns it to the environment.

Major infrastructure is not always visible. Sometimes, it is what works quietly

Facts & Figures

Project: West Side CSO Tunnel (Big Pipe), Portland, Oregon, United States

Completed: 2006

Built by: Lane Construction

Tunnel length: 5.5 km (18,180 ft)

Excavation diameter: 5 m (16.5 ft)

Pumping capacity: 120 million gallons per day (approximately 450 million liters)

Environmental impact: 94% reduction in untreated sewage discharges into the Willamette River

Technology milestone: First use in the United States of multimode slurry Mixshield TBMs for the excavation of a tunnel of this type.