Feasibility Study: In June 2014, the Alabama State Port Authority (ASPA) submitted a request to the U.S. Army Corps of Engineers to consider increasing the depth and width of the Mobile Harbor Channel. Specifically, the request asked the Corps of Engineers to investigate the feasibility of taking the channel to authorized dimensions under Section 201 of the 1986 Water Resources Development Act (WRDA).
Under the 1986 WRDA, the authorized dimensions for the majority of the channel were set at 55 ft. deep and 550 ft. wide. The constructed dimensions of the majority of the channel at that time were 45 ft. deep and 400 ft. wide.
The General Reevaluation Report (GRR) study began in late 2015 as a four-year, $7.8 million effort cost-shared with the ASPA. The results of the study were documented in a GRR and released to the public in July 2019. The recommendations provided in the study were approved by Major General Diana Holland, Commanding General of the U.S. Army Corps of Engineers, South Atlantic Division, and a Record of Decision was signed on September 6, 2019.
Construction: Construction occurred over seven construction phases with substantial completion in October 2025. Plans, specifications, and other documentation associated with each construction phase are provided in the "Plans and Specifications" link on this page.
Phase 1 construction consisted of deepening in the southernmost portion of the bar (entrance) channel. Phase 1 construction is complete.
Phase 2 construction was implemented in two sub-phases. Phase 2 construction deepened the lower bay channel and widened part of the lower bay channel to allow two-way traffic. Phase 2a was awarded August 2024. Phase 2a and Phase 2b construction is complete.
Phase 3 began just north of the widening for a length of approximately 12 miles in the lower bay channel. Phase 3 construction is complete.
Phase 4 deepened the remainder of the lower bay channel and a portion of the upper bay channel. Phase 4 construction is complete.
Phase 5 deepened the upper bay channel to the turning basin. Material was beneficially used in the Relic Shell area in Mobile Bay. Phase 5 construction is complete.
Phase 6 included deepening the remainder of the upper bay channel and modifications to the turning basin. Material was beneficially used in two shoreline protection projections and the Relic Shell area in Mobile Bay. Phase 6 was awarded May 2024. Phase 6 construction is complete.
Relic Shell Area Monitoring: Two field studies were conducted to better understand sediment retention and water quality implications associated with in-bay strategic placement of dredged material within former oyster-shell mining areas within Mobile Bay, Alabama as part of the Mobile Harbor Deepening and Widening project. Deployed instrumentation and periodic campaigns of bed and water quality sampling provided data prior to dredged-sediment placement through more than a year after placement. Bed sampling and acoustic sub-bottom profiling indicated that the dredged material deposit was spatially variable in thickness and composition. Placed sediment accumulated quickly, within hours of placement, followed by a 2–4 month period with relatively small adjustments. Beyond 6 months, bed elevation changes became stable at near-background levels. Water quality data indicated that impacts to dissolved oxygen and turbidity associated with the dredged material placement are minor and short-lived. Notably, all water quality parameters remained within the normal range of variability observed within the dynamic Mobile Bay ecosystem. Collectively, these sediment bed and water quality studies support future data driven BUDM decision-making within the Mobile Bay region.
The full report resulting from the studies is available at: https://erdc-library.erdc.dren.mil/entities/publication/0d2123a8-dc69-42b7-9267-354130d06e83
Operations and Maintenance: The Mobile District US Army Corps of Engineers is responsible for maintaining the Mobile Harbor Federal navigation channel to the constructed depths. More information for the ongoing maintenance activities is available at: https://www.sam.usace.army.mil/Missions/Program-and-Project-Management/Civil-Projects/Mobile-Harbor-Project/Mobile-Harbor-Operations-and-Maintenance/