Industrial

The West Side CSO tunnel is a 14-foot diameter, 3-1/2 mile long tunnel that captures sewage and storm water on the west side of the Willamette River. The tunnel extends from SW Clay Street to Swan Island. The confluent shaft is on Swan Island. The shafts connect the existing sewer system to the new tunnel and will be used for long term operations and maintenance access.

The tunnel boring machines (tbms), Lewis and Clark, both began excavation from the Nicolai shaft. Lewis completed the journey north, under the river to the confluent shaft and now to the Swan Island Pump Station shaft. Clark completed its journey and broke through at the Clay Street shaft.