Critic to Armor All
By Sheila Grissett
Forensic investigators have said that building levees and floodwalls without lining them with rock or concrete was a fundamental flaw in the hurricane protection system that failed during Hurricane Katrina.
And yet, 18 months later, the region's levees remain largely unarmored and are likely to stay that way for the next two or three storm seasons. And, to the dismay of scientists monitoring the Army Corps of Engineers' efforts to patch together the region's flood defenses, in some places the unarmored levees already have deep cuts caused by rainfall pounding their unprotected crests.
All of the postmortems on the catastrophic failure of the levee system -- some by independent scientists, done by the corps itself -- acknowledge that scouring and other forms of erosion played a key role in the collapse.
While the toppled floodwalls that breached the 17th Street and London Avenue canals were the result of different processes, far and away the most extensive levee failures -- some of them miles long -- resulted from water cascading over floodwalls and washing away the soils below or sloshing up and down against the levee surfaces until they disintegrated.
There are several methods, some permanent and some temporary, to armor levee surfaces and floodwall footings against these destructive forces, among them blanketing the levees with concrete slabs, rock, synthetic fabric or some other covering.
In the months after Katrina, the corps quickly armored some floodwall footings, utility crossings and transition points where earthen levees meet hard structures that were damaged by the storm, and then went after money to armor undamaged sections of the system as well.
In January, the corps made an urgent request for $600 million to armor much or most of the 360-mile system of levees, but at the request of the Bush administration, corps officials whittled that to $170 million.
That would allow for armoring only the most vulnerable spots; the only levees to make the short list have been the Mississippi River-Gulf Outlet and one reach in eastern New Orleans.
"In lieu of armoring the entire system, selective armoring of levees and floodwalls could be accomplished to achieve some of the benefits at a reduced cost," Assistant Secretary of the Army for Civil Works John Paul Woodley Jr. testified before the Senate Appropriations Committee in March.
"The administration has proposed that armoring should be placed at such critical areas as pipeline crossings, the back sides of levees and floodwalls most exposed to storm surge, and areas where floodwalls transition to earthen levees."
Dragging it out
But the start date for doing even that significantly scaled-
back job is mired in the sluggish process the corps is following to complete, restore and improve the whole system of levees, floodwalls and gates.
Under its current, tentative schedule, even limited additional armoring isn't likely to be finished until the start of the 2010 hurricane season.
"Obviously, if we started on the MR-GO levee this year, it would be finished sooner than that," said Dan Hitchings, civilian administrator of the New Orleans corps district and director of Task Force Hope.
"And I'd like to tell you that will be the case, but I can't. Until we get all the additional information needed, we can't finalize plans and come up with a firm construction schedule."
Among missing data are surge and wave estimates required to be certain the armoring is sufficient to repel a "100-year-storm," the benchmark that the corps has been authorized to meet, but not exceed. The definition of a 100-year storm is not expected to be complete until early next year.
"Without a final, technically competent, fully blessed 100-year elevation, the corps can't finalize a plan," said Ed Link, the University of Maryland senior research engineer who is directing the corps' forensic review of the levee failure.
"They're already working feverishly, using their best, conservative estimates. They aren't sitting around doing nothing," said Link, who for three decades ran the Waterways Experimental Station, the corps' water management think tank in Vicksburg, Miss.
The money for post-Katrina levee work finally was approved last June as part of a special $3.6 billion hurricane relief bill, and corps lawyers are guiding the agency in developing revised procedures for spending and accounting for the money, another time-consuming, paperwork-heavy routine.
The process by which the Corps of Engineers is bound is a very complicated one," Task Force Hope Deputy Director John Meador wrote recently in a corps newsletter. "Most people are unaware of the many steps in the process, which frustrates those who would like to see the work accomplished as quickly as possible."
Critics are floored
Frustration over the levee repairs has given way to deep dismay among outspoken corps critics Robert Bea, who studied the catastrophe for the University of California-Berkeley and the National Science Foundation, and Ivor van Heerden, the Louisiana State University hurricane expert credited with helping to force the corps to concede that many of the levee failures were attributable to design flaws, not just overtopping.
Both men say the corps should move immediately to armor the front and back sides of all levees exposed to the Gulf of Mexico and Lake Pontchartrain, and that includes levees that didn't fail during Katrina, but could potentially fall during the next big storm.
"In our estimation, given the catastrophic failure of the MR-GO levee during Katrina, it would be prudent to armor them right now for waves and overtopping," said van Heerden, who led the state-fielded Team Louisiana probe.
"The bottom line is, New Orleans is unsafe and the MR-GO levees are unprotected, as are the Lake Pontchartrain levees," he said.
"If we got a Katrina-type storm that came west of the city over the airport or just west of the airport, we have the potential to see bigger waves on Lake Pontchartrain," said van Heerden, a co-founder and deputy director of the LSU Hurricane Center.
"We need to recognize that those levees could also be subject to significant wave attack and potential failure, especially if there's a strong wind out of the northeast or northwest."
Bea, a geotechnical engineer on the Berkeley campus and a former chief engineer for Shell in New Orleans, said he fears that the corps, where he once worked, is reverting to its old ways and acting without a sense of urgency.
The same thing happened after Hurricane Betsy struck the city in 1965, Bea said.
Bea, who lost his home to Betsy, is concerned that the same loss of momentum that afflicted the corps after that hurricane is settling over the post-
Katrina rebuilding process. Despite the acute shortcomings of the levee system laid bare by Betsy, Bea said, "they didn't really begin to work until the early 1990s and, as a result, the system wasn't finished when Katrina got here."
Bea said he can't understand why the federal government isn't providing all the money needed after several forensic investigations, including an examination sponsored by the corps itself, identified the lack of armoring as a prime culprit in the system's failure to protect the New Orleans area.
But if it was my world and I didn't have much money, I'd get out there with Visqueen and start nailing the damn stuff down," Bea said. "That pile of dirt won't do what you want unless you protect it. We need to secure what we've got, and it's irresponsible not to.
"You can make the world so complex that it takes 25 years to straighten it out instead of a couple of days," said Bea, who agrees with van Heerden that lakefront levees could fail if a major storm tracked just west of the city. "The corps has got to stop doing that."
Van Heerden said there are at least four methods for temporarily armoring the levee while the corps develops its ultimate plan. While none of them would provide sufficient protection, it beats doing nothing, van Heerden said.
Already, rain has clearly washed gullies of varying sizes -- the worst of which, van Heerden said, measured three feet deep -- in sections of the MR-GO levee where there is no grass cover.
One of the options would be to spray a temporary layer of blacktop up to an inch thick on the crest and both sides of the levee, van Heerden said, noting that it's an element of protection that Dutch water managers use on their state-of-the-art flood defense against North Sea tempests.
"It's critical to armor MR-GO levees now, and there are some simple ways to do it," van Heerden said.
Hitchings readily admits that the corps is having problems growing grass along MR-GO levees because of high salinity, and he said he's not ruling out temporary fixes to stabilize the back side of the levees if there isn't a good growth of grass by the start of the 2007 hurricane season.
He also wants the public to know that even without armoring, the new levee is much stronger than the one that washed away during Katrina. It's higher, wider and substantially stronger, and built with much better materials, he said.
"It would perform much better in another Katrina-type storm," he said. "You would get some surface erosion if that occurred before we got some armoring out there, but you wouldn't see the same catastrophic destruction."
Hitchings said the lakefront levees were not considered for the high-priority list because they performed well during Katrina.
But Bea said that while some of the lakefront levees were made of good soils, they weren't fully tested because they were spared the brunt of the surge or were buffered against destructive wave action by wetlands or a protective structure.
"A flood protection system is like a chain that breaks at its weak links," Bea said.
His concern is that the sections of the levee system that didn't break during Katrina are in all likelihood the new weak links. And those weak links cry out for as much strengthening as is physically possible before the next big storm, he said.
Watching his pennies
Although corps research and development teams have been studying what to armor and how to do it since January, there is still no final word on the strategies they propose to implement.
"It was decided that a more detailed analysis was needed to ensure the best answers," Hitchings said.
Once an armoring design is chosen, it will be incorporated into the work of raising and otherwise strengthening the system to provide 100-year protection, whenever that gets defined.
"You don't want to armor now and have to rip it out when it's time to raise the levees," said Kevin Wagner, who oversaw the emergency rebuilding of levees in St. Bernard as part of Task Force Guardian, the accelerated corps effort to patch up the region's flood defenses ahead of the 2006 storm season.
"We want to make the best use of our money," said Wagner, now the corps' project manager for levees, floodwalls and armoring.
"Our research and development people are working to determine the best-engineered design," he said. "And they've already found out that one type of blanket armor actually rolls up when the water rises."
If the research and development findings determine that additional sections of the system should be armored in the next phase of work, or that $170 million isn't sufficient to do the job, Hitchings said the corps would take a new request forward.
"We made a commitment to the administration that if we find that it isn't enough to do the job we need to do, we'll come back to them."
Col. Jeffrey Bedey, director of the corps' Hurricane Protection Office, said his agency won't know if more money is needed until the 100-year storm has been defined and construction plans are finalized.
In 2010, the flood protection system must be certified as being able to provide the protection required by the National Flood Insurance Program.
"I cannot envision being able to certify (a protection system) that doesn't have protection from scour," Bedey said.
But that protection may never be systemwide. "Armoring is not something you do carte blanche everywhere. If you try to start armoring willy-
nilly, you could be wasting a lot of limited resources that could be better applied in other areas," Link said.
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