Flood structure closed; crest now predicted to be 7.5 feet

Local officials battened down one of the world’s biggest hatches Monday, closing the Bayou Chene Flood Control Structure. The Atchafalaya River is expected to crest at Morgan City at 7.5 feet April 25.
That prediction was increased from 7.25 feet over the weekend.
As of Tuesday morning, the river was at 3.92. The Atchafalaya is expected to hit the 6-foot minor flood stage Sunday and the 7-foot moderate flood stage Wednesday, April 23.
The prediction is for the river to hit 7.5 feet April 25 and stay at that level for about a day.
The closure of the Bayou Chene structure went smoothly Monday, said Tim Matte, executive director of the St. Mary Levee District. The district operates the structure.
The structure works by moving a 400-foot barge, mounted on pins, across the bayou and filling it with water to settle it into place.
It’s designed to block back flooding along the bayou when the Atchafalaya runs high.
The barge was moved into place between 7 a.m. and 8 a.m. Filling it with water took until about 2 p.m., Matte said.
Construction of the structure, which was completed in 2022, followed years of lobbying by local lawmakers for state funding.
The final yes came down in 2019, when the Coastal Protection and Restoration Authority picked up the $80 million tab.
Expect Stephensville and Belle River residents to watch this flood closely. They often got the worst of back-flooding in a series of floods 2011-19.
The current flooding for now seems likely to cause more inconvenience than damage along the Atchafalaya. Not so for the Mississippi River
“Along the Mississippi, it could bring moderate or maybe even major flooding in a couple spots,” State Climatologist Jay Grymes told the Plaquemine Post South. “As the Mississippi goes, so goes the Atchafalaya because of the diversion at Old River control.”
Thirty percent of the Mississippi’s flow is diverted into the Atchafalaya at Old River.
“Even Morgan City, while area inside the floodwalls will get inundated, this will not be a rise outside the norm for the springtime period,” he said. “The good news for the Mississippi is that it should go up and go right down, but it may take longer the Atchafalaya to drop off once it gets up in those minor and moderate flood levels.”
On Monday in New Orleans, the Corps of Engineers began patrolling the levees along the Mississippi River twice weekly until the water level drops below 11 feet at the Carrollton Gage.
USACE initially entered Phase I flood fight Feb. 24 of this year and then paused operations when the water level at the Carrollton Gage dropped below 11 feet March 13.
Phase I is a proactive measure that is triggered when the Mississippi River reaches 11 feet at the Carrollton Gage and is forecast to continue to rise. The increased patrols help ensure our ability to respond quickly to any problem areas that may develop along the levee system because of the elevated water levels.