John Hall, a spokesman for the Army Corps of Engineers, said last night that the corps and other agencies were "in a great frenzy" to figure out how to plug the 300-foot gap along the 17th Street Canal.The narrow canal, which is used to drain water pumped out of the eternally soggy city, is not accessible by barge, in part because a newly built low bridge and hurricane barrier sits 700 feet down the canal toward the lake end. "We can't get at it," Mr. Hall said.

Engineering challenges... is putting it lightly. Its going to be a hard week in the Big Easy.

I must admit that the full impact of this storm was not clear to me until I saw the TV last night, even though I expected it to be bad.

For years I have made the joke that I'd like to see New Orleans before its completely destroyed. Today, I'm feeling bad about making that joke. And its not because I still have not spent any time down in New Orleans.

The sheer human tragedy present on everyone TV screens today is heartbreaking. What's worse, is we saw this coming. The failures present here were all preventable at multiple stages. It starts with the fact that its not a good idea to build a city below sea level, and it ends with evacuation plans that were clearly not mature enough to deal with the reality everyone knew was coming.

The big question: What do we rebuild? And what do we abandon?

Geography Complicates Levee Repair - New York Times