Death and taxes may be the only certainties of life in the rest of the nation, but residents of southeast Louisiana have one more: subsidence.
Getting a sinking feeling on this geologically starving delta is a physical rather than emotional event, and something scientific instruments confirm is taking place 24/7, 365.
That’s why the local flood protection authority has made a proactive request of the U.S. Army Corps of Engineers: Before you armor our levees at your expense, let us raise them by an amount equivalent to what will be lost in 10 years of subsidence — at our expense.
It’s all about staying certified for the National Flood Insurance Program.
The Southeast Louisiana Flood Protection Authority—East knows its levee system must be re-certified for insurance 10 years from now. And it knows it will need to raise much of the system at that time because subsidence will have dragged it below heights needed to qualify for flood coverage.
“Well, they are putting the armoring on now [at federal expense], but we know we’ll have to destroy it to lift the levees later, then re-armor them again,” said Tim Doody, president of the Southeast Louisiana Flood Protection Authority—East.
“If we can do the lifts now before they armor the levees, we could save $20 million,” he said. “We estimate — in round numbers — it will cost $30 million to raise the levees to meet the certification after 10 years of subsidence. It will cost another $20 million to redo the armoring if we wait until then.”
All of southeast Louisiana rests on deltas built by the annual floods of the Mississippi River for 6,000 years. Once levees were completed in the 1930s to prevent those floods, the delta became starved of sediment and began sinking, a process geologists say will eventually pull much of the area below sea level.
Doody said next Wednesday his agency will sit down with the corps and the state’s Coastal Protection and Restoration Authority to discuss the proposition.
“The corps has said they aren’t sure there is enough time for us to do this,” Doody said, “but we’re going to do our best to work this into the schedule.”
Corps of Engineers spokesman Rene Poche said, “What’s being suggested seems a reasonable and responsible approach to sustaining the performance of the system. We are hopeful that we can make it work, but ultimately our decision will be based on meeting our commitments to public safety.”
