Willamette River Water Treatment Plant

"Addressing a City's Inadequate Water Supply"

How can an Oregon city address an inadequate water supply so it can lift a moratorium on new development?

That was MWH's challenge as design/build contractor of the US $43.8 million Williamette River Water Treatment Plant (WTP) for the city of Wilsonville. The project was delivered on a fast track — just 28 months after notice to proceed. This was just in time to meet the city's increased water supply needs caused by area growth and construction of a new state prison.

Speed did not affect the WTP's performance, however.

The Willamette River WTP was named "Best of 2002" in the category of Outstanding Public Project for Oregon by F.W. Dodge's Northwest Construction magazine. The regional monthly industry publication applauded the project's careful balance of technological excellence with its contributions to the environment and society. (Link to www.northwest.construction.com)

Innovative "Actiflo" Process

Located south of Portland, along the Williamette River, the 10-acre project involved building:

• A 15 million gallons per day (mgd) water treatment plant (with an ultimate capacity of 70 mgd)
• A 120 mgd raw water intake facility in the Willamette River
• A five-acre city park

The Willamette River WTP uses the latest disinfection and filtration techniques. It also features an innovative clarification process called "Actiflo" to improve settling speed within a small footprint.

MWH designed the operations to function as both a public works facility as well as a public park. To create an appealing facade, architects used materials such as stone, brick, wood and textured concrete in the exterior wall facing the park.

The site features a 5-acre landscaped park with ponds cascading over stone walls. It also has pedestrian paths meandering through an open meadow to the bluff above the Williamette River.