Floods

Two cares can be seen underwater during the Great Flood of 2016.

In 2016, an unnamed storm dropped over, in some areas, three feet of rain on the Amite and Comite River basins.

The result, called the Great Flood of 2016, pushed the Amite to 46 feet at Denham Springs and caused widespread devastation who’s dollar total continues to climb, even three years later.

After the disaster, a windfall of funds has come from the federal government – albeit some of those dollars have come easier than others. Included in those streams was $350 million to fully fund the Comite River Diversion Canal – a project that had been on the books since 1980 and had a ‘start-and-stop’ relationship with the state of Louisiana, Department of Transportation and Development (DOTD), and Corps of Engineers.

A task force for the project was created in the early 2010s, helmed by state Representative Valarie Hodges of the Watson area, and backed by U.S. Congressman Garret Graves (R-District 06). Eventually, the project found the plan and funds to become a reality, and completion is expected by the second quarter of 2021.

Recently, the Corps and DOTD presented the timeline to the task force, also informing them that land acquisition was the final piece of the puzzle. 58 parcels remained outstanding that were waiting for appraisals. The project called for the pieces of the canal to be built in sections to avoid overall delays if a study focused on one section came back, for instance, saying that an endangered species of turtle lives in the area.

Instead of stopping the whole project, that section would shut down construction as the turtles are either relocated or a new path is drawn up for the canal, and then the project would move forward.

That’s just one potential ‘show-stopping’ event, but the plan is working so far, according to DOTD, who reaffirmed the second quarter of 2021 completion date. The project would have reduced the crest of the Amite River in the Denham Springs area by 1.5 – 2 feet, for conservative estimates.

But what about 7 feet?

According to the next report, courtesy of Sam Crampton of Dewberry Engineering, that’s exactly how much lower the Amite’s crest would have been in 2016 if the Darlington Reservoir had existed, Crampton explained. Between the two projects, the crest of the river would have been closer to 37 or 38 feet.

According to Crampton, Dewberry designed models that tracked the rainfall and flooding in 2016, and used that to create new data that would show flooding should the Comite and Darlington exist. Darlington, which would be located 40 miles upstream from the confluence of the Comite and Amite Rivers in St. Helena parish, is currently slated to be an 800,000 acre, dry storage reservoir.

The three mile dam would have a flow-through area near the center, with the river’s current path, running through box culverts that would control the flow of the Amite. Should the water level exceed the culverts, the river would rise with the 90-feet tall dam structure, filling the reservoir.

Should the water reach the top of the reservoir, a safety spillway would take excess and roll it downstream back into the Amite.

According to Crampton, this would provide multi-foot crest protection for 700 square miles of the basin leading to Denham Springs, and over 1200 square miles if areas south of the Amite and Comite confluence are included.

Representative Charles Saucier, of Louisiana’s 5th District, asked Crampton how a structure 40 miles north of places like Watson, Central, and Denham Springs could help in a rain event such as the one in 2016.

Crampton explained that in an event with that much rain, which was almost all dumped on the Amite and Comite basins, water flows south. Structures like the Comite and Darlington have little effect on flash flooding, he explained, which is the duty of local governments. However, large scale flooding events are caused by widespread rainfall over a large area, so having upstream protection is invaluable.

Crampton cited one scenario, wherein the storm was based on top of Denham Springs with small bands to the north, and said the Darlington still would have reduced the water level by 4-5 feet.

Darlington being ‘dry’ was chosen as a cost-savings measure, much to the chagrin of some local officials in Livingston and St. Helena, who believed a ‘wet’ reservoir – or a lake – would draw new commerce to the area, including residential homes, recreation, and business.

However, according to the Corps and DOTD’s models, having to dig out a lake and reinforce the soil would be more expensive than building the dam structure and a wall to hold the water.

Those models also show that the cost of the project has soared since it’s initial proposal in the 1980s. Then, a $100 million estimated price tag was applied to the Darlington Reservoir, which was roughly equal to the Comite Diversion Canal’s proposed cost.

State budget issues, petty politics, and – according to former publisher Jeff David – the involvement of ecologists killed the project at that time.

The cost of the Darlington has far surpassed the Comite this time around. $1.8 billion is the total applied for Alternative-13, which is the name given to the Darlington if it’s a dry reservoir.

Hodges was unphased by the cost, pushing the Corps on a timeline for the project – to which she was told at least two years until congress would approve the project through the corps.

According to a corps engineer, the Darlington is part of a larger feasibility study that is three years long – and is currently just in year one.

“It’ll be at least two years before congress will even approve the project,” he explained, “and that’s only if the feasibility story turns it out as a good project.

“Then you have to find the funding,” he added.

Hodges asked if the timeline could be skipped, to which the corps representative responded that it could, because DOTD is the local sponsor on the project. In theory, he said, they could go ahead with the project and apply for acceptance as a flood-mitigation implement with the corps at a later date.

Hodges pushed DOTD representatives in the room to present a timeline for moving forward locally on the project, saying there was no time to wait due to increased chances for the event to happen again and, citing congressman Graves, prevention is cheaper than recovery.

“Trillions of dollars have been spent on recovery,” Hodges said, “and weather patterns have changed – we could have 10 hurricanes between now and the time this project is approved.

“This bad weather isn’t going to stop.”

(1) comment

douglascore

If this study is even close, and it would knock seven feet off of the record flood, then I’d hope all of our elected officials would get onboard and make it happen.

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