Katrina, the Argument

The evening after Katrina hit I picked up bits of news as I was walking about the State Fair and learned that New Orleans had pretty much passed through the "storm of the century" unscathed, there would be no "New Atlantis", and I felt satisfaction that the excited anticipation of the press had been disappointed.

The next day I found there was flooding. "Okay," I said, "patch the breaks." But one day later I learned there was a "catastrophe" and I said to myself: "Something is screwed-up."

There is now no one who doesn't recognize that everything about New Orleans was very "screwed-up", the only question is the specifics and the blame. I'm going to focus on the failure of the floodwalls.

First, how much stress did the floodwalls experience?

From the very first it was said: "The levee system was built only to withstand a Category 3 hurricane. It faced a Category 5...Whoops, a Cat 4. What can you expect?" In fact the WaPo article of yesterday argues it was a Category 3. Very possibly it was only a Category One.

There's some evidence for this in a reassessment of wind speeds being done by NOAA. This reassessment is standard. Hurricane Andrew came ashore as a Category 4, after reassessment it was determined to be a Category 5 and is now so classified. Katrina, the most devastating storm of the century may, at the point of the 17th Street Canal failure, eventually be reclassified as Category One. That would be interesting.

First, two obvious observations: the floodwalls didn't fail until the second day; and the roof tops, seen from the overflying camera, were at the point of the break, in just fine shape, not a tile or a shingle missing.

Here's the article taken from -1 Prometheus: Katrina as Category 1 in New Orleans? Archives , originally appearing in the Oct 4 addition of the Florida Sun-Sentinel.

"Hurricane Katrina might have battered New Orleans and the Gulf Coast as a considerably weaker system than the Category 4 tempest initially reported. New, preliminary information compiled by hurricane researchers suggests the system struck southeast Louisiana on Aug. 29 with peak-sustained winds of 115 mph. That would have made it a Category 3 storm, still a major hurricane, but a step down from the enormous destructive force of a Category 4. Katrina might have further downgraded to a strong Category 1 system with 95 mph winds when it punched water through New Orleans' levees, severely flooding most of the city and killing hundreds. The levees were designed to withstand a Category 3 storm. If verified, the wind information compiled by the National Oceanic and Atmospheric Administration's Hurricane Research Division could have chilling ramifications.

According to hurricane research division findings, Katrina remained a Category4 until it was about 105 miles south of the Mississippi River delta. In downtown New Orleans, the winds were barely hurricane strength because buildings disrupted the flow...


So it's possible that the winds at the point of failure of the 17th Street Canal were not even at hurrican strength! Yet they fell over. Of course, this doesn't consider storm surge, but whatever the surge was it wouldn't have been over something expected of Cat One, and that, certainly, should have been contained by walls built to withstand Cat 3.

But they failed.

Why?

The only conclusion can be that they were defective, either in design, or in construction. (There is argument that a Category 4 storm surge pushed through into Lake Ponchatrain. I dismiss that.)

Some speculation here is in order:

An initial explanation given by the Army Corps of Engineers was that the floodwalls had

The evening after Katrina hit I picked up bits of news as I was walking about the State Fair and learned that New Orleans had pretty much passed through the "storm of the century" unscathed, there would be no "New Atlantis", and I felt satisfaction that the excited anticipation of the press had been disappointed.

The next day I found there was flooding. "Okay," I said, "patch the breaks." But one day later I learned there was a "catastrophe" and I said to myself: "Something is screwed-up."

There is now no one who doesn't recognize that everything about New Orleans was very "screwed-up", the only question is the specifics and the blame. I'm going to focus on the failure of the floodwalls.

First, how much stress did the floodwalls experience?

From the very first it was said: "The levee system was built only to withstand a Category 3 hurricane. It faced a Category 5...Whoops, a Cat 4. What can you expect?" In fact the WaPo article of yesterday argues it was a Category 3. Very possibly it was only a Category One.
There's some evidence for this in a reassessment of wind speeds being done by NOAA. This reassessment is standard. Hurricane Andrew came ashore as a Category 4, after reassessment it was determined to be a Category 5 and is now so classified. Katrina, the most devastating storm of the century may, at the point of the 17th Street Canal failure, eventually be reclassified as Category One. That would be interesting.

First, two obvious observations: the floodwalls didn't fail until the second day; and the roof tops, seen from the overflying camera, were at the point of the break, in just fine shape, not a tile or a shingle missing.

Here's the article taken from -1 Prometheus: Katrina as Category 1 in New Orleans? Archives , originally appearing in the Oct 4 addition of the Florida Sun-Sentinel.

• "Hurricane Katrina might have battered New Orleans and the Gulf Coast as a considerably weaker system than the Category 4 tempest initially reported. New, preliminary information compiled by hurricane researchers suggests the system struck southeast Louisiana on Aug. 29 with peak-sustained winds of 115 mph. That would have made it a Category 3 storm, still a major hurricane, but a step down from the enormous destructive force of a Category 4. Katrina might have further downgraded to a strong Category 1 system with 95 mph winds when it punched water through New Orleans' levees, severely flooding most of the city and killing hundreds. The levees were designed to withstand a Category 3 storm. If verified, the wind information compiled by the National Oceanic and Atmospheric Administration's Hurricane Research Division could have chilling ramifications.

• According to hurricane research division findings, Katrina remained a Category4 until it was about 105 miles south of the Mississippi River delta. In downtown New Orleans, the winds were barely hurricane strength because buildings disrupted the flow...

So it's possible that the winds at the point of failure of the 17th Street Canal were not even at hurrican strength! Yet they fell over. Of course, this doesn't consider storm surge, but whatever the surge was it wouldn't have been over something expected of Cat One, and that, certainly, should have been contained by walls built to withstand Cat 3.

But they failed.

Why?

The only conclusion can be that they were defective, either in design, or in construction. (There is argument that a Category 4 storm surge pushed through into Lake Ponchatrain. I dismiss that.)

Some speculation here is in order:

An initial explanation given by the Army Corps of Engineers was that the floodwalls had been over-topped, erosion at the outside base occurred, the base weakened, the walls failed. I don't believe that's true, any more than I believe that Lake Ponchatrain was filled by a Category 4 surge; but I don't believe it was a lie, I don't believe it was a cover-up, I think it was an attempt to give a rational explanation of the otherwise inexplicable. But it's not the right explanation.

The first "clue" I heard pointing in the right direction (unattributed) was this musing: That the walls that failed seemed to be the walls that had just been rebuilt. This isn't really a "clue", it's in fact, thee explanation, just minus the details: They were built bad.

Lisa Myers of NBC has done some excellent work on this in a Sept. 30 article containing this PDF regarding Pittman Construction .... But I see it's getting late. Perhaps I'll do further work later. Right now I want to see if my links work.