Many areas of Watson and Denham Springs flooded during the torrential storms of August 2016.

The U.S. Army Corps of Engineers advanced a plan Monday to build a dam along the Amite River near Darlington in its effort to limit flooding in heavily populated areas of East Baton Rouge, Ascension and Livingston parishes.

If completed, the $2.3 billion project would create a flood pool of just under 20 square miles along the East Feliciana-St. Helena parish line. The dam itself would cover 205 acres, according to a draft of the project’s feasibility study.

There is no timetable for when work would begin if the Corps and ultimately Congress gives the Darlington Reservoir the green light.

All told, the project footprint includes an area covering about 24 square miles. The Corps would relocate nearly 400 structures, including a church and its nearby cemetery. Other flood-relief work involves elevating more than 3,000 residential structures and flood-proofing another 300 nonresidential structures.

“That’s why it’s essential we have public input on this,” said Dietmar Rietschier, executive director of the Amite River Basin Commission. “There are going to be several meetings on this. And it’s important for them to know we are long way off from seeing this done.”

The Corps will hold the first meeting on the proposed project Dec. 17 at 6:30 p.m. at the North Park Recreation Center in Denham Springs. The following day, Dec. 18, it will hold another meeting at 6 p.m. at Clinton United Methodist Church in Clinton.

The feasibility study, which was funded up to $3 million through the same Bipartisan Budget Act that included money for the Comite River Diversion Canal Project and East Baton Rouge Parish’s Flood Control Project, is just a preliminary step in the project’s road winding road to fruition.

Matt Roe, a public affairs specialist with the Corps of Engineers, said after gaining public feedback within the 45-day public review, the Corps would have to draft a final report for the project before it heads to the U.S. Congress for authorization and funding.

Roe said the Corps is about halfway through a three-year study period looking at ways to better protect the region.

The Corps posted a draft of the plan on its website.

Rietschier, who on Monday hadn’t reviewed the draft of the study yet, added that local government entities in the region would also have to come up with the matching funds to do the project.

“That’s standard for these Army Corps of Engineering projects,” he said.

The Corps has studied potential flood-control measures along the Amite and its tributaries for decades, but the effort picked up a faster pace after the 2016 floods swamped thousands of homes in the region and closed parts of the interstate highway system for several days.

The renewed focus on flood mitigation that has happened of late at the local, state and federal levels reinvigorated interest in the Comite Division project and East Baton Rouge Parish’s Flood Control Project, which involves the clearing, dredging and widening of five tributaries in the parish. And the same appears to have occurred with the Amite River focused project as well.

The feasibility study evaluated several options to address flood mitigation along the 2,200 square miles of the Amite River Basin, which includes parts of counties in southwestern Mississippi as well as Ascension, East Baton Rouge, East Feliciana, Iberville, Livingston, St. Helena, St. James and St. John the Baptist parishes – all of which are impacted by backwater flooding along and near the Amite River.

The Corps said the dry dam and reservoir near Darlington were found to be the most impactful regarding reducing flood risk for the area.

According to the study, the Dry Darlington Dam would have a footprint of approximately 205 acres and a flood pool of approximately 12,600 acres. The outlet would consist of three 10-foot by 10-foot concrete box culverts with sliding gates to control water.

An emergency spillway would be integrated at the flood control pool, the study says.

Many of the details surrounding abutment requirements, channel dimensions, access roads and staging areas for construction haven’t been determined yet, the study states.

An emergency action plan and flood warning system for the dam and its downstream flows would be decided later. Each parish impacted by the proposed project would be responsible for developing their own floodplain management plans related to it.

Roe noted that, as the Corps continues to study the project going forward, the impacts related to the completion of the Comite River Diversion Canal project and the East Baton Rouge flood mitigation projects will be taken into consideration.

The Corps said plans for the dam project also includes elevating 3,252 homes and flood-proofing 314 non-residential building, plus additional work inside the area that would become the flood pool.

The dam would require the Corps to acquire 15,860 acres, affecting approximately 700 landowners. According to their initial evaluations, there are approximately 365 “residential and non-residential” structures that would have to be moved. The Corps also said the Church of God in Christ and its adjacent cemetery would need to be relocated outside of the limits of the planned reservoir for the dam.

Relocation assistance would be provided to those that would get displaced and be factored into the final costs for the project, the study states.

“Having the public come out to these meetings to have that level of participation is really important right now,” Roe said.

Email Terry Jones at tjones@theadvocate.com