Not sure if this graphic has heights or not. Try it and see. I have one that does but there are a lot of levees and they're all different heigths. it's too big to post too. and I don't have a direct link.
http://www.nola.com/hurricane/index.ssf?/washingaway/goingunder.html
There's another possibility too. If just one of the locks' gates are open, then it wouldn't change the wording of the article necessarily, and they would be worrying about it, but there wouldn't be a flood from that cause yet.
Not sure it matters.
The London Canal breach repair has been undermined by percolation and is leaking. Per janetjanet998 here, 6 to 8 inches of water in some neighborhoods of downtown NO.
Another report has sand boils uder downtown levees.
Not trying to be alarmist, but fixing a breach under pressure is a very difficult proposition in any weather.
No panic, no hysteria, but NO stands a good chance of flooding again.
OK, I'll finally bite: I take it a sand boil is water percolating up, and producing visible sand?????? I have been wanting to ask that since yesterday. What exactly are sand boils? TIA
Good chart. Answers the question. Mississippi average is 14 feet above sea level, Mississippi levees are at 21.4, Lake surface is 1, Lake leeves 14.5, Bourbon street is high ground at 2.5. So even if the Lake goes up to match the River the city is still protect by SIX INCHES. If the River is in Flood or the Lake has storm surge pressure - whoops. Or if you have weakened levees - whoops.
Your good post raises another question. Who in their right mind would think you CAN fix a levee without building coffer dams? It is going to take months to make NO "safe" as it was and that was not-very. They really need to rethink this and use a Dutch system of concentric rings with nothing of value 'cept cows in between. I do not understand the rush to pump.
This Fox guy Hemmer is all aggitated about water flowing back into the ninth ward. Give him back to CNN. Time to write off the ninth ward.