Posted on July 29, 2020
Residents of six coastal and river parishes will no longer have to rely on old barges to block flood waters from the Atchafalaya River.
State and local levee managers have begun work on an $80 million floodgate at Bayou Chene near Morgan City that will provide longer-lasting protection for the portions of St. Mary, Terrebonne, Lafourche, St. Martin, Assumption and Iberville parishes that are under growing risk from backwater flooding during the Atchafalaya’s high-water periods.
The floodgate will replace temporary barges that have been used at same location four times. Barges were temporarily sunk across the bayou during flooding and high water periods in 1973, 2011, 2016 and 2019.
Crews prepare a barge that was sunk in Bayou Chene in 2019 to reduce backwater flooding in the area.
Courtesy of Christian J. Gil
“Thankfully, sinking barges has been successful, but it is a costly and short-term approach,” Gov. John Bel Edwards said in a statement. “This permanent structure will provide a reliable, long-term solution for the people and businesses in this area.”
The project’s funding comes from energy revenues via the Gulf of Mexico Energy Security Act, or GOMESA.The state Coastal Protection and Restoration Authority and the St. Mary Parish Levee District are overseeing construction.
During high Mississippi River events, about 30% of the river’s flow is transferred into the Atchafalaya River system near Baton Rouge. High water in the Atchafalaya begins backing up through Bayou Chene, moving from west to east around Morgan City and then north, where it can overtop levees and wetland buffer areas, causing flooding.
A photo of a temporary barge gate being installed in Bayou Chene in 2019 to protect against backwater flooding in the Morgan City area.
St. Mary Parish Levee District
The project’s permits were approved in May 2019, more than five years after it was first proposed.
When deployed, the floating, 400-foot-long floodgate will swing into place between steel walls. It will then sink into place, with its top about 10 feet above sea level.
The CPRA estimates the project will protect an area with about 100,000 people.
John Boudreaux, an Assumption Parish emergency preparedness manager, said the barges have already proved the floodgates will work
“It’s been proven many times over,” he said Thursday. “We know it’ll benefit a lot of people.”
The floodgate would also be deployed when the Morganza Spillway is used to ease pressure on Mississippi levees. The spillway’s opening sends floodwater over land, affecting farms, communities and wildlife, making it a controversial solution for high water on the Mississippi. It has only been opened twice, in 1973 and 2011.
The floodgate and other components of the project, including road improvements and an earthen levee, are expected to be completed by September 2021.
Source: nola
