The Multnomah County Board of Commissioners is set Thursday to authorize the sale of $128 million in bonds to pay most of the county’s share to replace the Sellwood Bridge.

The county ultimately will pay an estimated $9 million in financing charges to pay off the bonds. The money will come from a county surcharge on motor vehicle registration of $19 per year, during the next 20 years.

Some $18 million has already been collected in county vehicle registration fees, which also will be used for the bridge project.

Additional money for the Sellwood Bridge replacement is coming from the city of Portland ($84.5 million), the state ($35 million) and federal government ($33.5 million.)

County commissioners will review the bond proposal at about 10:50 a.m. Thursday, in the county headquarters at 501 S.E. Hawthorne Blvd.