My sister lives in New Orleans and my cousins live across Lake Pontchartrain. I’ll admit I wasn’t overly concerned about them in the immediate aftermath of Katrina in 2005. I knew my sister had evacuated to my cousins’ place in Mandeville, and I knew they were all headed north from there.

The final path and intensity of the storm also meant that New Orleans would be spared truly catastrophic wind damage.

But then sometime late on that Monday morning in 2005, I heard a TV news report of a levee breach, accompanied by an inane reassurance that New Orleans was not filling up like a bowl of water. Since much of the city is below sea level, there was no way that some neighborhoods couldn’t be filling up. Of course, as it turned out, there wasn’t just a single levee breach, and all areas of the city were already flooded or were flooding up to at least sea level.

In the immediate aftermath of those breaches, the Corps of Engineers tried to place some of the blame on corruption of New Orleans officials, but just last week a Corps official backed way off from those accusations. From Nola.com on August 22 of this year, Corps of Engineers critic repeats accusations of shoddy work:

Rosenthal also took the corps to task for its past accusations that New Orleans officials bore some responsibility for the canal failures because they pressured the corps to pursue an inferior storm protection plan. For instance, she said the corps blamed local officials for forcing it to reinforce the canal walls rather than build floodgates without pumps at the mouth of the three outfall canals.

The commanding general of the corps in Katrina’s aftermath, Lt. Gen. Carl Strock, told the New York Times in June 2006 that the corps accepted responsibility for the levee failures. Earlier this year, he told The Times-Picayune that his statements about local officials’ roles were not intended to be deceitful.

“Throughout our response to Katrina I emphasized how critical it was to be transparent and honest if we were to regain the trust of the public,” he said. “I might have illustrated my description with things I had heard but not personally researched, but there was absolutely no intent to deceive anyone.”

Rosenthal made a public-records request for any documents that supported the corps’ allegations that they were pressured to build up the canal walls and not install floodgates. In February, Ken Holder, chief of public affairs for the corps’ New Orleans District office, responded that the corps couldn’t determine which documents Strock and his second-in-command, Major Gen. Don Riley, used to make such claims.[. . .]

Rosenthal said Wednesday that “the evidence speaks for itself.” She added: “It seems pretty clear that the reason the corps can’t produce the data is because it doesn’t exist.”

Next, let me share two images from Tulane geology professor Stephen A. Nelson’s amazing field guide to the Katrina levee breaks, Hurricane Katrina – What Happened?. My sister Nancye is one of Nelson’s colleagues. First, a map of New Orleans in 1878, showing development on the highest ground, and then a map from the Times-Picayune showing the depths of the flooding about two weeks after the storm:


Here’s the official Katrina forecast map at 11 p.m. on August 26, 2005:

Here’s the official Isaac forecast map at 8 p.m. on August 26, 2012:

Here’s the latest on Isaac’s likely storm surge levels from Nola.com:

The threat to southeastern Louisiana is likely to include storm surges of between 6 and 12 feet above sea level, up to 12 inches of rain, with 20 inches possible in some locations, and sustained winds of 100 mph and higher gusts for much of the coast, depending on the exact location of the storm, according to the Slidell office of the National Weather Service. Its forecast calls for winds of 60 to 80 miles per hour on the north and south sides of Lake Pontchartrain, with gusts to 100 mph.

Water levels are likely to reach 5 to 7 feet above sea level in Lakes Pontchartrain and Maurepas, and 7 to 11 feet in Lake Borgne and south along the coast on the east side of the Mississippi River. West of the river, water heights could reach 9 feet.

National Hurricane Center Science and Operations Officer Chris Landsea said Sunday that while still only a tropical storm with sustained winds of 60 mph on Sunday, Isaac is huge, with tropicalstorm-force winds extending out 200 miles from its center.

So, barring a rather dramatic change in the track, this looks like the first really big test of the New Orleans levee system since Katrina. Those levees have obviously been repaired, but well enough?

I know everyone wants to project a sense of calm and confidence, but I think it’s inexplicable that New Orleans Mayor Mitch Landrieu has not called for an evacuation of all neighborhoods below sea level. By tomorrow morning, we’ll already by within 36 hours of projected landfall. Louisiana Governor Bobby Jindal has called for voluntary evacuations in a number of parishes but sounds confident in levee protection:

State and local officials are taking a number of steps to protect our people and property from the storm. In addition to issuing a State of Emergency for the storm, we are in touch with parish leaders and we are recommending voluntary evacuations within the hurricane watch area. Specifically, this is for people in low lying areas, areas outside of levee protection, and areas south of the Intracoastal Waterway.