The Columbia-Snake River System has paused operations for two weeks as the Portland District of the U.S. Army Corps of Engineers conducts its annual navigation lock maintenance.  Bonneville Lock will be closed through March 14, and The Dalles and John Day locks will be closed through March 21.  At Bonneville Lock, crews will partially dewater the chamber to inspect and repair recent damage, replace timber beams on the gates, and upgrade control systems to improve reliability and safety.  At The Dalles Lock, a full dewater will allow crews to add new instrumentation to the upstream gate wire ropes, inspect previous repair work, and install additional armament on the upstream gate.  And at the John Day Lock, crews will fully dewater the lock to complete concrete and weld repairs around the tainter valves, inspect and repair electrical feeds, and replace critical downstream gate trackwheels to support long-term system reliability.  During the closure, recreational boaters will be unable to pass through the navigation locks along the Columbia-Snake River System.  Boaters should plan accordingly and seek alternative routes or launch sites upstream or downstream of the locks. Public access to some areas near the locks may also be restricted for safety reasons.