You see my problem?
The New Orleans drainage and pumping system has the theoretical capacity to move about 40,000 gallons of water a second, or about twice the flow over the American Niagara Falls.
A temporary storm surge overtopping might be handled until the surge retreats. A hole in the bottom of a floodwall is different. A hole in the bottom of a floodwall will flood until the lake and the interior are at the same level, even if the sun is shining, the birds are singing, and the storm surge is ancient history.
Why the hell am I bothering?