LoMo navigation lock repairs to temporarily affect navigators, cross-dam drivers
– NavLock to temporarily close April 21 for valve repairs
– Public traffic may experience crossing delays
KAHLOTUS, Wash. – Lower Monumental Dam’s navigation lock will be temporarily out of service April. 21 to allow repair of the lock’s tainter fill valves, according to U.S. Army Corps of Engineers navigation officials at the Walla Walla District.
Inspections conducted Aug. 19 of tainter valve 4, one of two valves used to fill the lock, revealed cracks developed in its lifting-eye mechanism, causing it to malfunction. While this does not prevent the lock from being used, it does take twice as long to operate the lock having only one functioning valve with which to fill, explained Glen Matlock, Lower Monumental’s resident engineer who is supervising the valve repair.
The repairs to the valve have been ongoing since April 4. Most of the repairs have not required that the lock be taken out of service. However, finalizing the repairs will require a 12-hours shutdown to allow the contractor uninterrupted access to valve 4.
The 12-hour outage will begin at 7 a.m. and end at 7 p.m., allowing the contractor to conduct repairs and replacement of the valve’s trunnion pin assembly.
The valve 4 repair is estimated for completion by early May. After Thursday’s temporary outage, Corps officials anticipate the lock will remain in service while the repair work is completed.
Travelers wishing to cross Lower Monumental Dam may encounter delays as cranes are maneuvered on top of the dam. Travelers are encouraged to check the dam-crossing information line for crossing updates 1-888-DAM-INFO (1-888-326-4636).
The Corps has notified commercial navigators and other stakeholders of the temporary outage. The Corps coordinates navigation maintenance with inland shippers and cruise lines to achieve minimal impact to the various industries that use the locks. Public Notices and other navigation lock information are available on the Walla Walla District website at http://www.nww.usace.army.mil/Missions/Navigation.aspx.