91ÊÓƵ

A Portland Water Bureau project to construct a seismically resilient water supply line under the Willamette River will move forward after Portland City Council on Wednesday approved a $73.5 million design-build contract with Dallas, Oregon-based James W. Fowler Co.

All six existing pipes that deliver water west across the river are either suspended under bridges or buried in loose soils, making them likely to fail during a sizable earthquake. City officials estimate that restoring water services to the west side after a major seismic event could take up to 12 months, during which time revenue loss could total $3 billion.

As part of the Willamette River Crossing Project, crews will install a new water main 80 feet beneath the bed of the river in the Troutdale Formation, where it won’t be susceptible to damage from soil liquefaction. Because the majority of the crossing cannot be accessed from the surface by normal trenching techniques, the roughly mile-long alignment will be installed in part via horizontal directional drilling, while micro-tunneling construction will take place on the east side.

The proposed alignment of the new line will begin near the intersection of Southwest Harbor Drive and Naito Parkway, pass under the RiverPlace area and under the river to the north end of the OMSI property before terminating near the intersection of Southeast Seventh Avenue and Stephens Street.

The project’s total cost is $90 million, which includes $4 million for consulting, $6.5 million for permits, easements and property, and $6 million in contingency. The contractor has committed to 35 percent utilization of COBID-certified subcontractors, suppliers and manufacturers; including 6 percent utilization of emerging small businesses.

Design of the project is expected to be completed in about a year, with construction to finish in October 2021. Total completion is expected in January 2022.