Flood authority talks hurricane readiness, levee sinkage plans

Published: Jun. 2, 2015 at 9:42 PM CDT|Updated: Jun. 2, 2015 at 10:19 PM CDT
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NEW ORLEANS, LA (WVUE) - The flood protection authority for the east banks of Orleans, Jefferson and St. Bernard parishes feels good about the levee and floodwall conditions for this hurricane season.

But, despite the billions spent by the U.S. Army Corps of Engineers, the Southeast Louisiana Flood Protection Authority is planning to spend millions because of emerging sinkage issues.

"Everything is really good shape this year, no big problems any place," said Bob Turner, Regional Director of SLFPA.

He said the authority oversees 105 miles of levees in Orleans Parish alone, another 60 miles in St. Bernard and 30 miles in East Jefferson. And while there are no spots to speak of currently, levee sinkage is on their radar.

"We live in a sinking delta, okay, the entire delta here is subsiding, Turner said.

The lakefront levee in East Jefferson is being looked at for future lifting.

"That runs about 11 miles along the lakefront, and there are segments of that levee that look to us that in the next year or two to be below the required design height just by a little bit," Turner said. "Several of the projects along there - considering raising those. We've got some engineering work that's going on right now to determine if it's feasible to do that."

The flood authority has its eye on parts of eastern New Orleans, as well.

"We have a couple of projects out in New Orleans East area, primarily out where the twin spans are," Turner said.

The Corps agreed that subsidence comes with the territory.

"Levees require maintenance throughout their life, and because many of these levees in this system were new and built on new alignments, the rate of settlement and subsidence is greater at the beginning, so that's why you see some of these levees need their first maintenance 'lift' between now and 2025 to maintain that original design elevation," said Col. Richard Hansen, Commander of the Corps New Orleans District.

Sinkage is a concern for good reason. It can have serious consequences.

"More water will get into the system over the top of the levees for even a 100-year even, so it's called over-topping. That over-topping amount will increase as the levees settle," Turner said.

The Corps is responsible for certifying levees, and sinkage issues can affect flood insurance.

"That certification is based upon the system being kept at the required design height, and so as it falls below that height, there is the potential that we could lose that certification at some point in time and then the insurance premiums could then become a big issue," Turner said.

Still, currently there is no cause for alarm.

"There are no portions of our system that are below the design requirements for the 100-year surge event, however, in just a few years we could have some have some sections that fall below that design required height, and so we are looking at the possibility of trying to raise those levees in the very near future - even before the Corps puts the armor on them, so we don't have to take the armor off in just a couple of years," Turner said.

"If you have, say, a 16-foot levee and it's 15 and 3/4 feet high, the level of risk reduction is not significantly changed, Hansen said. "But again, there's always that potential for a larger storm, which could cause greater over-topping, so residents still need to be ready."

Recently, the SLFPA commissioners passed a resolution identifying segments of levee that should be raised, and a program manager has been hired. The expected levee-raising project is expected to cost between $15 million and $35 million.

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