NOLA levees not overtopped?

News stories have said that Hurricane Katrina was a cat 4 and New Orleans levees were built to withstand a cat 3. However, Katrina made landfall quite a bit east of New Orleans, which meant that NOLA did not get cat 4 winds, rains, or flood surges. It turns out that the surge was 11 feet and the floodwalls were supposed to handle 14 feet.

But with the help of complex computer models and stark visual evidence, scientists and engineers at Louisiana State University’s Hurricane Center have concluded that Katrina’s surges did not come close to overtopping those barriers. That would make faulty design, inadequate construction or some combination of the two the likely cause of the breaching of the floodwalls along the 17th Street and London Avenue canals — and the flooding of most of New Orleans.
Experts Say Faulty Levees Caused Much of Flooding By Michael Grunwald and Susan B. Glasser Washington Post Staff Writers Wednesday, September 21, 2005; Page A01

  In other words, New Orleans never should have flooded. And, as we all saw on TV, the floodwaters ran over the levees for days before they were stopped.

Congress authorizes flood- control projects — after receiving recommendations from the Corps — and the Corps oversees their design and construction.

John M. Barry — who criticized the Corps in "Rising Tide," a history of the Mississippi River flood of 1927 — said that if Katrina did not exceed the design capacity of the New Orleans levees, the federal government may bear ultimate responsibility for this disaster.

"If this is true, then the loss of life and the devastation in much of New Orleans is no more a natural disaster than a surgeon killing a patient by failing to suture an artery would be a natural death," Barry said. "And that surgeon would be culpable."

And those same floodwalls are overflowing again during Hurricane Rita. Apparently the repairs after Katrina were no better than the original construction.


7 thoughts on “NOLA levees not overtopped?

  1. John Charles Griffin

    Regarding floodwalls, levees ,and protection from flooding, there have been numerous “Monday Morning Quarterbacks” with various debates about who’s to blame and what went wrong in New Orleans. One impractical question asked on your blog regarded repairs after Katrina not holding up during storm surges of Rita. Basically the engineers working on patching up after Katrina simple did not have time to complete non-destructive testing of the structure before Rita rolled in. The keyword here is “patching up.” A patch does not create a new pair of britches
    or a semblance thereof. Levees over time will need to be rebuilt
    and studies regarding successful flood control models in Holland should become part of structural planning equations.

  2. John Quarterman

    If I patched my britches and they broke the next time I wore them, I’d be mad at myself; if I paid somebody to do it, I’d want my money back; and if the Corps of Engineers patched my levee and it broke the next time there was a hurricane, I’d want an independent investigation.
    As the Economist has pointed out, if 1,000 dead and a hundred billion in damages aren’t worth investigating, what is?

  3. John Charles Griffin

    Agreed Army Corpse of Engineers leadership often a slippery bunch of folks, but again with Rita’s surge an around the clock repair project had to be abandoned by
    levee earth movers and reinforcement machinery. Some of the subcontractors had to depart repair central via boat because water was rising & winds too strong for helicopter flight. I’m not defending the Army Corpse but my point is that when Rita arrived
    levee construction workers had a choice to either stay and drown,
    drink liquor and climb whatever trees remained, or get out of there until winds diminished and waters subsided.

  4. John Quarterman

    So you’re not saying that the levees were patched; rather that the patches weren’t complete. OK, fair enough.
    However, the question remains as to why they failed in the first place, especially given that the winds and storm surge they experienced appear to have been no greater than they were supposed to be designed for.
    Once again, if 1,000 dead and $100 billion in damages aren’t worth an independent investigation, what is?

  5. Kelleher, William J.

    I’m a 78 year old retired engineer with a BCE and MSCE. Most of my professional career was with the state of New York as a Radiological Health Engineer. However I taught sanitary engineering, soil mechanics and foundations in college for eight years. After I retired I became involved in a very bitter controversy in my home town over an infiltration gallery on the Hudson River built within 15 feet of a wooden sheet piled dike built by the Corps of Engineers in 1830 and replaced in 1865 and 1915. The controversy led to my own investigation of the Corps. The following is my opinion of what caused the floods in New Orleans.
    The flooding of New Orleans that followed hurricane Katrina was not an-act-of-God nor was it the fault of Congress, Presidents Clinton and Bush for not providing more monies to improve the canal levees that pass through the city itself. The loss of hundreds of lives and the living nightmares experienced by thousands of survivors was clearly the result of engineering malpractice on the part of the United States Army Corps of Engineers.
    When the elevations of the canal levees were raised in the 1990s one of the contractors that built the new concrete flood walls put in a claim for additional money because an existing flimsy sheet pile and the soft soil caused major delays in pouring and curing the concrete walls. A hearing was held, one witness for the Corps testified that the existing sheet pile could have been tin foil, it made no difference in the pouring and curing of the walls. The contractor’s claim was rejected.
    There were over six expert witnesses who testified at the hearing. None questioned the well known fact that a single cantilevered sheet pile embedded in soil is not an acceptable permanent foundation for dams or floodwalls over seven feet high. Further the Corps’ own manual requires that this type of dam or floodwall be analyzed to make sure that the overturning moment caused by the height of water can be resisted by the sheet pile and the soil in which it is embedded. The overturning moment is a function of the height of water cubed. This means the overturning moment for 10 feet of water is eight times greater than for 5 feet of water. The Corps designed floodwalls 6 to 11 feet high attached to a flimsy existing cantilevered steel sheet pile embedded in the existing earthen levee.
    Hurricane Katrina caused the water levels in the canals to rise up into the new flood walls. At some elevation the bending moment on the combined sheet pile caused it to deflect increasing the effective height of the water on the wet side of the levee. As the cantilevered sheet pile started to tip over the sheet pile and soil had to resist the height of water over the entire depth of the combined levee. At one breech the force of the water pushed the concrete and steel sheet pile out 35 feet. The explosion heard by nearby residents was probably caused by the massive tearing apart of the sheet piles and the whipping off of the reinforced concrete flood wall from the steel sheet pile. The failure of the new floodwalls caused the existing earth levee to fail, it would have been better if the new floodwalls had not been built.
    A very important question that the President and Congress must answer is why continue the funding of levees on all of the canals within the city of New Orleans? What commercial benefit justifies the lost of human lives and over $200 billion in damages. These canals should have been filled in or damned off years ago. A new modern pumped storm water system can be built to keep New Orleans dry after a rainstorm.
    William J. Kelleher, 182 Roweland Avenue, Delmar, NY 12054, 518-439-6281,

  6. John Quarterman

    That is a good question about the canals: if they’re that risky, why are they really needed?
    Regarding which president is to blame, which one was president for four years before it happened, which one was elected saying he was the best candidate to protect the safety of the American people, and which one has spent hundreds of billions of dollars on homeland security and the military that neither prevented nor alleviated this disaster?
    Regarding the inadequate construction, I’d like to see an independent investigation funded by Congress, with people like you involved. As the Economist said:
    “A thousand people have died and the tax payer faces a bill of up to $200 billion. If those two things do not merit independent investigation, then what on earth does?”

  7. Kelleher, William J.

    I have asked members of congress and President Bush to make an independant investigation of the sacred cash cow. Unfortunately the poor people of New Orleans will be pitted against the full power of the federal government and if their attorneys are successful, which is unlikely, the US taxpayers will have to pay. This assumes the displaced people can find attorneys and enginers willing to take the risk. At the Washington County Fair E-coli trial a state appointed judge ruled that the state of New York could not be held liable regardless of how incompetent the engineers in the state health department were.

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