ON BAYOU CHENE — Barring no delays from strong currents, parish officials said they are confident work to sink a barge and fortify this area south of Amelia should be complete by Tuesday afternoon, about 1½ to 2 days before water is expected to arrive from the Morganza Spillway.
St. Mary Parish Levee District President Bill Hidalgo said this morning that as of Sunday night, 504 feet of sheet-piling had been driven into the waterway, much of it in the center, and armoring has been installed, which will be used for erosion.
Today, he said sheet-piling work would begin on the Avoca Island side of the bayou.
As closure of the waterway increases, so do the challenges, though.
“It gets more restricted so the velocities are increasing, so it becomes a bigger chore to do it,” Hidalgo said of the sheet-pile driving.
Still, he said things are going well and that the velocities have not been so bad that it has stopped work.
The barge will be placed north of the area where a barge was sunk in 1973 to slow down backwater flooding in multiple parishes, including St. Mary, Lower St. Martin and Assumption parishes. The reason is mainly because the elevation of the water here is 5 feet, which is higher than the location the barge was placed during the 1973 flood. Everything south of the current barge site has a decreasing elevation.
The goal of the structure is for floodwaters to hit the sheet-piling in front of the barge and after it builds up, for gravity to pull it down into the area marshes. The goal is for it to replenish these starving marshes with nutrients on its way to the Gulf of Mexico.
“As far as projections where the water should go once it hits, this is going to be the best cost-effective” method, Parish Levee District Executive Director Allen Kelly said.
The barge, he said, is there to provide fortification for that sheet piling so it does not bend or fail.
“There’s going to be a lot of pressure on those sheetpiles,” Kelly said.
He said the barge would not stop backwater flooding. Rather, he said, the goal is to slow it down.
Rock also will be placed along the waterway’s banks to help with currents, Kelly said.
Following the flood fight — which could last as much as three weeks — the frame of the structure will be left in place and the barge removed. If necessary, it could be repositioned in the near term.
“Is it a long term fix?” Kelly asked. “No, but it is a structure that we could use in the near term.”
The levee district has future plans for a permanent floodgate that will be used to help with backwater flooding pushed into the area from hurricanes. However, it could be used for riverine flooding events, such as this current one.
The barge for the current project, which was obtained from McDermott International’s Amelia yard, is about 480 feet long and about 30 wide and designed for sinking.
“In fact, it won’t even touch the bottom,” Kelly said.
The barge will be lowered approximately 25 feet in the bayou, while the sheet-pile will be driven the full 30 feet.
In preparation for the project, both sides of Bayou Chene’s bank have been dredged.
The barge was in use before the project, and Kelly said it would be used after its use as a flood protection structure is complete, he said.
Despite the recognition McDermott is receiving, the levee director said the project is more than just McDermott, as local workers from multiple companies have been used for the work.
“Sure, McDermott’s … got the biggest toy out here (but) everybody’s been very supportive,” he said.
The effect on local businesses is no secret, Kelly said, too, because Bayou Chene could be blocked for as many as three weeks, affecting commerce to some extent.