(KLIX) – Two bridge construction projects will begin Monday. Both will be on Highway 20, one each in Blaine and Camas counties.

Bridges will be built over Willow Creek in Camas County, at about milepost 164, and Rock Creek in Blaine County at milepost 173, according to the Idaho Transportation Department.

Traffic will be reduced to one lane through the construction zones and width restrictions are likely, the department said. Reduced speed limits and temporary traffic lights also will be in place.

ITD said the projects include removing aging culverts and surrounding earthwork at both locations and constructing new crossings over the waterways.

  • Willow Creek will be a 170-foot steel girder bridge.
  • Rock Creek will be a 159-foot concrete girder bridge.

Each work zone is anticipated to encompass one mile with about seven miles between each site. ITD said work is expected to last through December.

“Due to age and corrosion of the pipelines, both culverts are in need of replacement,” ITD Project Manager Brock Dillé said in a statement. “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.”