(The Center Square) — The U.S. Army Corps of Engineers is moving forward with a tentative plan for mitigating flood risk in the Amite River basin that will undergo public review early next year.
Kaitlyn Richard, project manager for the Army Corps, provided an update on an Amite River and Tributary Feasibility Study to the Amite River Basin Drainage and Water Conservation District at a meeting in Baton Rouge on Tuesday.
The project started in 2018 to assess flood risk management feasibility in conjunction with the Department of Transportation and Development for a 2,200 square mile area that covers 8 parishes in southeast Louisiana.
The effort initially resulted in a recommended plan for a dry Darlington Dam for $2.3 billion. Still, that plan was scrapped over various legal, technical and policy concerns during review.
The dam would have required officials to acquire 203 structures to make it happen, while other concerns centered on the impacts to “socially vulnerable areas” or those with low-income minority communities.
“There were potential for high adverse disproportionate and direct impacts to environmental justice areas and communities,” Richard said.
Further analysis, including hydrologic modeling and economic evaluations, led officials to a “non-structural” plan that involves elevating residential structures, flood proofing non-residential structures, and other risk mitigation strategies such as floodplain management plans.
After considering several options, the Army Corps ultimately came to a tentatively selected plan in October that would cost an estimated $1.56 billion to $1.66 billion to address 3,298 eligible structures, with a cost-to-benefit ratio of about .995. Of the 3,298 structures, 2,918 residential structures would be elevated up to 13 feet, while another 380 nonresidential structures would be dry floodproofed.
“These are all preliminary numbers,” Richard said. “We will be refining the costs and the benefits going forward.”
The Army Corps is now working on an implementation plan to be included in a final report. The Army Corps expects to release a draft report on Dec. 15, triggering public, agency, policy and legal reviews.
“That is going to kick off our public review period,” Richard said. “We are actually going to keep a 45 day public review for that because we are going into the holidays during that time, as well.”
“Right now that report has been drafted and it is undergoing internal reviews at the district,” she said.
The Army Corps expects to hold public meetings on the nonstructural alternative in early January.
Following public comment review, the Army Corps plans to make a final decision in February, with a final report in April 2024. A chief’s report from top Army Corps officials would come in July 2024.
“After that point, in order to move to construction you would still need congressional authorization and appropriations,” Richard said.
Some members of the Amite River Basin Commission noted the timeline for efforts to address flooding in the region dates back decades, and commended the Army Corps for closing in on a solution.
Others highlighted the “massive undertaking” of manpower and machines necessary to elevate thousands of structures, and how that work could expose structures to higher risk of wind damage, as well as hundreds of millions in local cost share to complete the project.
“Those are defiantly conversations that will occur before finalizing the report,” Richard said. “We would have to work those discussions through our nonfederal sponsor DOTD, but I would expect that would occur between now and April.”