A broken portion of John Day Lock and Dam’s upstream navigation lock gate has slowed Columbia River traffic.  U.S. Army Corps of Engineers technicians found the damage to a lower guide wheel on Monday, and closed the lock to river traffic.  Engineers and operations staff initiated limited lockage’s Tuesday evening in coordination with the U.S. Coast Guard.  Corps Portland District commander Col. Mike Helton says they are unsure what caused the damage.  Locks at Bonneville, The Dalles and John Day dams in February each year to make repairs, complete inspections and perform maintenance.  However, the Corps says aging infrastructure, wear and tear, and other issues have caused unexpected outages in recent years: in 2019, the Bonneville Lock needed emergency repairs for a sill block, and in 2021, district officials shut down The Dalles Lock for emergency repairs to a miter gate.  Portland District locks on the Columbia River pass 10 million of the 50.5 million tons of commerce shipped annually in the nation.