Lock replacement at three dams will bring river traffic on the Columbia and Snake River systems to a virtual halt Friday.
The closures will continue through March and affect both commercial craft and recreational boaters. Other dams in the Columbia and Snake River system will also be closed for maintenance starting in January.
The dams, all operated by the U.S. Army Corps of Engineers, are Lower Monumental on the Snake River and The Dalles and John Day dams on the Columbia River.
Lower Monumental Dam's lock return to service on March 14 and The Dalles and John Day dams' locks will both return to service on March 19.