French Prairie Bridge ProjectCity Council unanimously recommends two bridge types for further study in French Prairie Bridge Project

WILSONVILLE, OR — On Jan. 7, 2019, the Wilsonville City Council unanimously supported the recommendation of the French Prairie Bridge Task Force, designating two bridge types for further study among the five previously under consideration by the project team.

The proposed French Prairie Bridge over the Willamette River would provide a seismically-sound emergency response alternative to I-5 and connect the North Willamette Valley to the Portland metro area for daily use by bicyclists and pedestrians.

The 21-member Task Force empaneled to review and recommend an alignment and design for the bike-ped-emergency bridge recommended suspension and cable-stayed bridge types. Working in partnership with Clackamas County, the City Council agreed.

“These two bridge designs are the best options for Wilsonville,” said City Councilor Charlotte Lehan, co-chair of the Task Force. “These two signature-type bridges will have the lowest permanent impact on our waterways. Either one would provide an important and beautiful addition to our community, a memorable landmark that would attract visitors and complete an important regional trail segment.”

The bridge types under review are considered “signature bridges” as they are unique forms not commonly constructed. Building either bridge type would lessen the short-term impact on the marina, and neither would lead to permanent impacts on the marina or to the Clackamas County Boones Ferry Boat Launch parking lot. Neither relies on in-water bridge supports, reducing the complexity and timeframe for permitting.

The proposed French Prairie Bridge fills a critical gap in local and regional multi-modal transportation infrastructure, connecting the Portland metro area Tonquin Ice Age Trail and the northern portion of the Willamette Valley Scenic Bike Route. Currently, the only bridge crossing in a 30-mile stretch of the Willamette River in the south Portland metro area is the heavily trafficked I-5 Boone Bridge. Four-foot-wide shoulders of the seven-lane Boone Bridge serve as the only accessible bridge crossing by foot or bike.

The oft-congested Boone Bridge carries more than 120,000 vehicles daily — nearly a third of which are large trucks — and provides cyclists and pedestrians with no separation from traffic. When accidents or other traffic disruptions occur, back-ups on I-5 can impact emergency response time; secondary responders working to clear the road can have difficulty getting to the accident site. The proposed French Prairie Bridge would provide a safe route for cyclists and pedestrians to cross the Willamette River and an I-5 incident response alternative for emergency responders.

Project leaders must now determine a preferred bridge design, complete an environmental review and develop cost estimates. The Wilsonville City Council and the Clackamas County Board of County Commissioners plan to select a final bridge design this spring following further study of costs, design, and effects. When these tasks are complete, and the estimate cost of the project known, funding sources will be sought to construct the bridge.

Those interested in staying up to date on the project and learning about future events can sign up for project mailings at For more information, contact Project Manager Zach Weigel, P.E., at 503-570-1565;