Work Set to Begin on Wastewater Treatment Outfall Replacement

A map demonstrating the closure area.

July 9, 2018 – The City of Wilsonville is set to embark on a project to replace a 40-year-old corrugated metal outfall pipe and install a new diffuser at the Wastewater Treatment Plant.

The project provides increased wastewater treatment capacity to accommodate future growth, improves Willamette River water quality and satisfies Oregon Department of Environmental Quality (DEQ) compliance requirements.

Leakage from the outgoing outfall pipe was discovered in 2014; the City completed interim repairs on the outfall in 2015.

The Wilsonville City Council approved preliminary design and permitting or the replacement pipe in October 2015, and authorized final design and bid support in November 2016. In May 2018, Council authorized a contract with Northbank Civil and Marine to complete the $1.1 million replacement and diffuser installation. 

When completed, the improved system is capable of providing wastewater discharge capacity up to 7 million gallons per day.

I-5 Undercrossing Trail Closure

With construction set to begin this month, the City is closing the I-5 Undercrossing Trail each weekday, 7 am-6 pm, beginning on Monday, July 16. The closure is expect to extend until Friday, Aug. 17. 

While crews are working, trail access is unavailable east of Boones Ferry Park on Tauchman St. and west beyond the Kalyca Dr. cul-de-sac accessed via Wilson Lane. 

Pedestrian and bicycle access is available on weekends and outside of weekday construction hours, although a portion of the trailway will be covered by a metal plate, which could limit ADA access.

For more information on the Outfall Replacement Project, contact Zach Weigel, Engineering Manager, at 503-570-1565, weigel@ci.wilsonville.or.us.

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