1. Starting on or about 18 November 2025, USACE contractor Massman Construction will commence on a new 50-foot diameter guide cell downstream of Lock and Dam 25.  The new guide cell will be constructed approximately 340 feet downstream of the existing guide cell as referenced in the attached drawing.  There will be intermittent periods of active construction adjacent to the navigation channel throughout the duration of construction, which will continue to October 2026.  Mariners should be on the lookout for construction activities and related equipment to include barges, cranes, and work boats that will be working in the area.

2. As part of this work, Lock 25 will be closed on the below days and times to allow for dredging operations within the area of the new guide cell and to allow dredging equipment to works safely adjacent to the navigation channel.  The closure schedule for this work is updated, with a dates added on 12 and 15 December 2025. 

   • 18 Nov: 0800-1600 (8 hours)
   • 20 Nov: 0800-1600 (8 hours)
   • 24 Nov: 0800-1600 (8 hours)
   • 26 Nov: 0800-1600 (8 hours)
   • 1 Dec: 0800-1600 (8 hours)
   • 3 Dec: 0800-1600 (8 hours)
   • 5 Dec: 0800-1600 (8 hours)
   • 12 Dec: 0800-1600 (8 hours)
   • 15 Dec: 0800-1600 (8 hours)

    

3. Additional Lock closures may be required as the construction of the guide cell continues and this NTNI will be updated as the closure dates are identified.
4. All navigation interest should be alert for, and abide by, any special instructions that may be issued by the Lockmaster.

FOR THE DISTRICT ENGINEER: