Holt Lock Extends Its Weekend Navigation Pattern to December

The revised weekly access programme

The US Army Corps of Engineers has revised the navigation programme around permanent repairs to a damaged monolith at Holt Lock on Alabama's Black Warrior-Tombigbee Waterway. Bulletin 26-129, issued on 22 October, schedules continuous closure until 06:00 on 31 October, followed by a five-day closure and two-day opening pattern through an estimated 18 December. [1] Each weekly opening is scheduled from 06:00 Saturday to 06:00 Monday. The intervening five days are reserved for construction. The notice prints its times as CDT, including the period after the November clock change; operators need the district's confirmation of the operating clock when booking a passage. [1] The district's June bulletin had anticipated a 27 October-6 November phase using the five-day/two-day arrangement. The October revision moves the start of that arrangement to 31 October and extends its expected duration into December. Traffic plans based on the June programme need the revised weekly openings. [1, 2]

Arrival timing controls passage exposure

A two-day opening provides 48 scheduled passage hours in a 168-hour week. That is 28.6% of calendar time before accounting for lockage cycles, vessel queues and the way arrivals cluster around reopening. The access pattern concentrates demand at the same time that construction has exclusive use of the lock during the working week. For a tow approaching near Monday's cutoff, a missed passage can roll into the following weekend. Dispatch planning therefore needs an arrival margin, upstream and downstream holding arrangements, and the current lockmaster's instructions. A simple five-day allowance in an itinerary obscures the importance of the arrival day and hour.