Levee board begs corps to get a 10-year jump on subsidence — at local expense

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.”

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About Bob Marshall

From 2013 to 2017, Bob Marshall covered environmental issues for The Lens, with a special focus on coastal restoration and wetlands. While at The Times-Picayune, his work chronicling the people, stories and issues of Louisiana’s wetlands was recognized with two Pulitzer Prizes and other awards. In 2012 Marshall was a member of the inaugural class inducted into the Loyola University School of Communications Den of Distinction.

  • dimdingledon

    Another attempt by the SLFPA-E to cover up how poorly they have performed in overseeing the work done by the Corps of Engineers in rebuilding the flood protection system. The SLFPA-E is trying to sway public opinion that this is an effort to save money. But what they fail to mention is that they did not review the designs of the Corps of Engineers and were even told that the values of settlement used by the Corps were too low. The Corps of Engineers used a combine total of 1 foot for settlement and sea level rise. This was brought to the attention of the SLFPA-E on numerous occassions, but the leaders of the board elected to do nothing. The SLFPA-E did nothing to challenge the Corps on the design and let them proceed. But that is what you get when you let media created or self proclaimed flood experts act as decision making flood experts. See for yourself in your of them admitting they haven’t reviewed the work of the Corps of Engineers.

  • dimdingledon

    The original design and the storm surge modeling was inadequate and should be redone at full federal expense. The storm surge model used a suite of storms that were not reflective of our actual flood threat and caused a lower 100 year flood elevation to be established. 29 storm tracks with different intensity storms were run over and over the same storm tracks to get to the 152 magic statistical number. The SLFPA-E elected to let the Corps use this modeling to design the entire system. As a result, we got another system that was inadequate for out actual flood threat. We got another ystem in name only (ASINO).