The Idaho Transportation Department will begin work April 1, 2019 on two bridge construction projects along U.S.-20. The new crossings will be located over Willow Creek in Camas County (MP 164) and Rock Creek in Blaine County (MP 173).
During construction, ITD will remove aging culverts and surrounding earthwork at both locations, and construct new crossings over the waterways.
"Due to age and corrosion of the pipelines, both culverts are in need of replacement," said Brock Dillé, ITD project manager. "We analyzed multiple options regarding these crossings before determining that bridge designs would have the best long-term value for both Willow Creek and Rock Creek."
The structure spanning Willow Creek will be a 170-ft. steel girder bridge while the structure spanning Rock Creek will be a 159-ft. concrete girder bridge. As an added result of the forthcoming bridge structures, ITD also will be able to restore the streams to a more natural condition, which in turn should have a positive effect on the surrounding ecosystem.
Construction on the crossings will occur simultaneously. Each work zone is anticipated to encompass 1 mi. with approximately 7 mi. between each site.
Traffic will be reduced to one lane in the construction zone with width restrictions anticipated. Temporary traffic lights will be in place throughout the duration of the project and reduced speed limits will also be in effect.
Work is expected to last through December.
Knife River is the contractor for both projects.
