Corps approves $ 1.9 billion plan to keep hurricane levees elevated in the New Orleans area through 2078 | environment

The Army Corps of Engineers has given its final approval to spend $ 1.9 billion to keep portions of the hurricane levee system in the New Orleans area high enough for another half a century to prevent hurricane tides and waves from a so-called 100 -year-old storm to protect.

Approval will provide Congress with two separate plans to protect either side of the Mississippi from a storm with a 1 percent chance each year. They are calling for levees to be raised, some flood walls replaced, and new flood walls built as needed to offset the combined effects of earth solidification and settlement, sea level rise and fall, including higher water levels caused by global warming.

After the reports are passed, Congress would consider funding certain survey work in future annual corps budgets through 2078. The first dike lifting projects would likely not be completed before 2028.

The Corps’ approval of the plans shows the Biden government’s commitment to defending the New Orleans area for another 50 years, as climate scientists around the world anticipate stronger hurricanes and rising sea levels.

The east bank levee system, known as Lake Pontchartrain and Vicinity, would have 80 kilometers of levee lifts and 5 kilometers of replaced or new flood walls, costing $ 1.24 billion. The West Bank and surrounding system would include 49 miles of levee lifts, 1 mile of new flood wall and 268 feet of flood wall replacement. Plans also include raising portions of the Mississippi’s levees on both banks to keep pace with rising sea levels.

Approval from the Corps construction manager, Alvin Lee, guarantees that 65 percent of the costs will be borne by the federal government. The other 35 percent is paid for by the local sponsor, which is officially the state of Louisiana, although the East Bank and West Bank regional levees oversee the two levee systems and may pay some of the local costs.

Without the Corps’ approval of the elevation reports, the state and the two dike authorities would continue to bear the full cost of all major dike and flood wall improvements. Both authorities paid to raise their earth levees in advance to cover the higher storm heights of 1% and avoid the additional cost of replacing fabric mats that were used as armor on the flood side of the levees.

The corps is installing the mats as the last task of its 14.6 billion. If the dikes are raised after the armor has been installed, the mats would have to be replaced at considerable additional cost for the local sponsors.

Fifteen years after Hurricane Katrina exposed the New Orleans area levee system as a “system by name”, its redesign and reconstruction …

Lee was the commandant and district engineer of the New Orleans District Office of the Corps from 2007 to 2010 when much of the levee system was rebuilt. He is now overseeing all civil engineering work by the corps.

In agreeing to the profile plans, Lee adopted the Corps personnel’s findings that it is in the national interest to keep the levee system at a 1% risk level. If the system were not maintained at this level, the levees would settle to a lower height and areas within them could eventually lose eligibility for full coverage under the National Flood Insurance Program.

The reports estimate the financial benefits of improving the dike systems – preventing flood damage – at an average of $ 196 million per year for the east bank and $ 72 million for the west bank over the project’s 50-year life. However, the reports also confirmed that the levee elevation plans only consider the effects of storm surges and waves over the levees and not other flood risks, such as levee failure for other reasons.

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Seabrook Surge Gates graphic

Lee also agreed with employees that the cost of better protection – against a “200 year” storm with a 0.5% chance of striking in any given year – outweighs the benefits. The reports also state that Congress only approved 1% protection based on state flood insurance standards in effect in 2005.

The Corps itself has classified the levee systems in the New Orleans area as “high risk,” the second worst level, since a flood would cause more than 1% billion dollars in damage. This rating is based on the risks of climbing over and the other causes of dyke failure not included in the new dyke height reports.

Governor John Bel Edwards and other officials had called for 0.5% protection to be adopted to reduce future flood damage.

Since Hurricane Katrina, billions of dollars have been spent upgrading the ring of levees, flood walls, and pumping stations to …

Still, officials from the Louisiana Coastal Protection and Restoration Authority and local levees are pleased with the Corps’ decision to proceed with 1% protection. Coastal Authority executive director Bren Haase said a key feature of the plans is that the cost will be spread across the state and local levees over 50 years, allowing more flexibility to raise the local share of the money.

“We have seen the enormous benefits of increased flood protection on our coast, especially in the last two hurricane seasons,” said Haase. “We will continue to pursue and evaluate a higher level of protection for Greater New Orleans and other coastal areas, an issue that was identified in the 2017 Master Plan and will also be evaluated for the 2023 Plan.”

“We are very pleased to have received approval from the Corps for future levee lifts, and encourage Congress to allocate the funding necessary for such lifts,” said Kelli Chandler, regional director of the Eastern Bank Levy Authority. “Hurricane Ida clearly showed that the [levee system] has more than paid off by protecting the region. “

The West Closure Complex in Belle Chasse can be seen during a flyover off the Louisiana coast on Friday, May 18, 2018. The asset tour was organized by G …

She said the agency expects to pay part of the local share of the collection costs with funds already earmarked for this purpose in its budget.

Chandler said the agency expects to continue speaking with the Corps about increasing levee protection beyond the “100-year level” even as the city and state of New Orleans consider other “multiple lines of defense” to address surge risk to reduce, including elevating buildings and providing access to flood insurance.

“Raising the level of protection is something we would always advocate, and we will continue to engage our partners … to find ways to make the system even better,” said Chandler.

Nick Cali, Regional Director of the West Bank Authority, also praised the Corps’ decision, citing the success of the West Bank system in containing surges during Hurricanes 2020 and this summer during Ida.

He said the West Bank agency spent more than $ 23 million on dike lifts in 2020 and expects to participate in cost-sharing decisions for the new work with the state coastal agency and other local dike authorities.

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This work is supported by a grant from the Walton Family Foundation and administered by the Society of Environmental Journalists.

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