GONZALES — East Ascension drainage officials are embarking on a multi-year process to have the parish-built levee system accredited by the Federal Emergency Management Agency as providing protection from a 100-year flooding event.
If granted, the accreditation would mean reduced flood insurance rates for St. Amant, Acy, Lake and parts of Gonzales, parish drainage officials and their consultants said.
The only flood protection system in Louisiana with FEMA accreditation is the nearly $16 billion levee system that the U.S. Army Corps of Engineers rebuilt to protect New Orleans after the old federal system failed during Hurricane Katrina and devastated the city in 2005.
East Ascension Drainage Director Bill Roux told the drainage board last month that accreditation would put all parish structures in a special flood insurance zone — which some already have — but predicted the process could take years.
“We’re looking at five years probably at least to get it anywhere near certification, and we’re going to learn a lot over the first few months exactly what we have to do to get it certified,” Roux said.
Accreditation could require millions in new construction and possible upgrades, parish officials and their consultants have acknowledged. A 100-year flooding event is one that has a 1 percent chance of happening in any given year.
The East Ascension board has already been planning to build a $20 million northern extension of the Laurel Ridge levee system aimed at providing flood protection to low-lying parts of far eastern Ascension.
The 4.5-mile extension, as proposed, would cut through hardwood swamps from Gold Place Road, where the existing levee ends, and go northwest to Wall Cemetery Road just east of La. 431.
Working in concert with the Marvin J. Braud Pumping Station in McElroy Swamp, other pumps in Sorrento and a new floodgate at Henderson Bayou, the levee protects against rising water in the Amite River Basin. The basin is susceptible to heavy rains in the north and surge from the south during major storms.
The Pontchartrain Levee District is helping with the cost of the project, but the levee is one of the capital projects left to finish from a 2007 bond issue that created $61.2 million in one-time revenue for drainage work.
Some parish drainage officials also believe a levee system may have to be built in the Sorrento area to, in effect, close the loop around the south side of the east bank. While the new extension will be built to Corps standards, the much older existing Laurel Ridge levee may need upgrades as well.
Michael Enlow, parish engineering manager, said this week the levees will have to be certified by an engineer as meeting Corps design and construction standards. Then FEMA will consider whether to accredit the system as having 100-year protection, he said.
Atri Sen, a project manager with HNTB, said the first months of the work will involve collecting data.
“I think the first step is to figure out what the status quo is, figure out where you guys are and then potentially have FEMA and the Corps come in and say, ‘OK, what would it take for us to get it accredited by FEMA,’ ” Sen said.
He said a package would be developed then to bring the system to the 100-year standard.
The East Ascension drainage board approved HNTB’s contract Monday to handle the accreditation process after the firm beat out several others following a request for qualifications for the job.
The levee extension, one key link toward accreditation, also inched forward. After years of negotiations with the Corps and landowners over the levee’s route, parish consultants have recently submitted permit applications to the Corps, said Jake Lambert, GSA Consulting Engineers’ project manager who is working on the levee.
Parish President Tommy Martinez told the drainage board Monday that he and other parish officials have met with Col. Richard Hansen, commander and district engineer of the Corps’ New Orleans District.
Martinez said that while they discussed several projects, he told Hansen the levee permit and construction is the top priority.
“He asked me again, ‘What’s the No. 1 priority at this point?’ I said, ‘Laurel Ridge levee.’ He said, ‘No. 2?’ I said, ‘Laurel Ridge levee.’ ‘No. 3?’ I said, ‘Laurel Ridge levee.’ ”
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