A meeting room is ringed with easels holding posterboards that describe various aspects of the fish passage project. People mill about the room to look at the boards and discuss with Army Corps of Engineers staff.

Fish migration project keeps swimming upstream

Army Corps of Engineers presents proposed designs to public

by Sydney Cromwell

After more than a year of study, the U.S. Army Corps of Engineers has proposed its plan to create fish passages around two dams on the Alabama River, restoring migration from the Gulf of Mexico to the Cahaba River.

For several fish, snail and mussel species, migration and water flow are essential to their life cycles and creating new generations. The Millers Ferry and Claiborne dams, located in Monroe and Wilcox counties on the Alabama River, have prevented that migration along more than 200 miles of waterways since they were built in the late 1960s and early 1970s.

Environmentalists in Alabama have been concerned for more than a decade that the presence of these dams would lead to the decline or extinction of these species, including the rare Gulf sturgeon and elephant-ear mussel.

Read more from Southern Science about the environmental impact of damming rivers.

In Nov. 2021, the Corps of Engineers Mobile District partnered with the Nature Conservancy to fund a feasibility study looking at different options to reconnect the Alabama River around these two dams. The results of that study were released on May 1, followed by public feedback meetings in Birmingham, Camden and Monroeville on May 16-18. The complete presentation will be posted online, and Southern Science will share that link when it is available.

The Corps’ proposed plan is to build bypass channels around the dams, using rocks, soil and riprap to create pools that mimic natural river flow and gradually change the elevation by around a foot at a time, so fish can swim from the lower to the upper water levels. The channels would be located on the western bank at each site and would only be open to wildlife, not fishers or watercraft.

The Claiborne channel would consist of around 30 pools that average around 80 feet long. Millers Ferry has a steeper elevation, so the Corps has proposed a longer channel, consisting of about 44 pools averaging 200 to 210 feet long.

These bypass channels would not interfere with the regular operation of the two dams, which is particularly important for the hydropower generation at Millers Ferry. Portions of the west bank at each dam, including the West Damsite Hunting Area at Millers Ferry, would be temporarily closed during construction.

The estimated cost to build these two channels is $188 million, according to data the Corps presented at the public meetings. The cost will be shared by the federal government and the Nature Conservancy, split 65%-35%.

The Corps also considered building rock weirs — which are small, dam-like structures that slow water flow — instead of the bypass channels at one or both dams, but the cost estimates for these projects were all above $200 million.

Two line drawings, one overhead and one from the side, of the bypass channel. It show four slightly curved rows of stones, each with a row of scattered stones just downstream of it. Lines demonstrating the water flow extend left to right. In the side-on view, three outlines of fish are shown to demonstrate the movement of wildlife up each pool.
A diagram of an example bypass channel, with stones, soil and riprap used to create pools and flowing water for fish to travel around the dam. Courtesy of the U.S. Army Corps of Engineers.

Dustin Gautney, the chief of public affairs for the Mobile District of the Corps of Engineers, said at the Birmingham meeting that so far the public reaction has been positive, especially for the project’s environmental impact. There has been some concern from landowners located near the two dams, which is part of why these meetings are being held, he said.

The next stage for this project will be the Corps’ decision on whether and how to proceed, which is expected this fall. Final reports will be published sometime in 2024. The two fish passages will eventually need congressional approval before work can begin, so construction is still a ways off.

The U.S. Army Corps of Engineers is accepting public comments about the fish passage project until May 31. You can submit feedback by email at AlabamaFishPassage@usace.army.mil or by mailing a letter to:

Commander, USACE Mobile District
Attn: PD-EI (Alabama Fish Passage)
P.O. Box 2288
Mobile, AL 36628

Main article image of the May 16, 2023, public feedback meeting at Birmingham Botanical Gardens. Photo by Sydney Cromwell.

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