Actually there were three breaks and the longer they leaked the larger they became due to the erosion. Question is; where were the"dry dock" barges that the city should have had on standby in anticipation of any breeches? Why were so many pumps inoperable? Why didnt canals have gates, which could have been closed to remove pressure at breaks?
This is one of the more surprising things I noticed about the Katrina disaster. It amazes me that the engineers would be willing to vastly increase the surface area of the levee system. I have a hard time believing that any engineering analysis would not have put building canal gates at the highest priority. It's like a sea-going ship not puting hull isolation valves on their seawater supply mains because they assume that the pipes will always hold.
[sarcasm] I think George Bush took the barges away the week before because he doesn't care about black people.[/sarcasm]
Kanye's next rap--
The gap grew very large,
Cuz Bush took away the barge,
and left no one in charge
Seriously, you've posed an interesting question.