Mobile District Seeks Public Comments On Alabama Fish Passage Study

The Mobile Engineer District has released the Draft Feasibility Report and integrated Environmental Assessment (Draft FR/EA) of a study that aims to restore fish passage between the Gulf of Mexico, Mobile Delta and Lower Alabama River and the Cahaba River.

The motivation for the study is the long-term degradation of biodiversity and hydrology on the Cahaba River, Alabama’s longest free-flowing river, which begins near Birmingham and meanders southward until it enters the Alabama River.

At the heart of the study is a pair of locks and dams on the Alabama River: Claiborne Lock and Dam at Mile 72.5 and Millers Ferry Lock and Dam at Mile 133. Millers Ferry Lock was completed in 1974, while Clairborne Lock came online in 1970.

The Claiborne and Millers Ferry locks and dams are part of the Alabama-Coosa-Tallapoosa (ACT) River system, along with the Robert F. Henry Lock and Dam farther upriver. All three locks are Level 6 locks, meaning commercial lockages are by appointment only, with a minimum of 72 hours’ notice required.

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Commercial navigation interests remain on the Alabama River, and more than $8 million was spent last year to dredge the waterway toward its authorized depth of 9 feet. Additional dredging is planned for this year with the goal of returning the project to its authorized depth by the end of this year.

The Cahaba River enters the Alabama River above Millers Ferry Lock and Dam, with both Millers Ferry and Claiborne locks impacting water flows and biodiversity on the Cahaba. The “Alabama Fish Passage Study” assessed ways of restoring lost biodiversity, including the disappearance of the Alabama Sturgeon. The Nature Conservancy is the non-federal sponsor for the study.

After using a multi-criteria decision analysis (MCDA) to weigh a variety of strategies for restoring fish passage between the Gulf and the Cahaba River (including a “no action” option), the Corps’ tentatively selected plan is to construct a natural bypass channel at both Millers Ferry and Claiborne locks, designated “Alternative 5d” in the Draft FR/EA.

“This alternative provides connectivity to the Cahaba River while providing the most acceptable method of fish passage,” the Draft FR/EA states. “Thirteen federally listed threatened and endangered species benefit equally or more with Alternative 5d than any other alternative evaluated. Additionally, Alternative 5d is preferred by the non-federal sponsor.”

According to the Corps, the bypass channels outlined in Alternative 5d would not affect navigation on the Alabama River.

Total cost is estimated at $188 million, with an estimated $200,000 in annual operations and maintenance costs for the bypass channels. Construction would take about 2.5 years.

The Corps released the Draft FR/EA May 1, with the public review and comment window running through May 31. The Corps plans to hold public meetings May 16 at the Birmingham Botanical Gardens in Birmingham, May 17 at Wilcox Female Institute in Camden and May 18 at The Shops at 66 in Monroeville. Comments can also be emailed to or sent by mail to Commander, USACE Mobile District, Attn: PD-EI (Alabama Fish Passage), P.O. Box 2288, Mobile, AL 36628.