Levee question

[coolwater]

I heard Greta Van whatever say that more areas of the levee's were starting to give way. My question is, can the flooding get any worse than it already is if more parts of the levee give way or has it risen as high as it will get in the city?

[jpigott]

i think the flooding is probably as bad as its going to get b/c the lake level is the same as the level of flood waters in the city. I say that with this caveat, the levee would need to be in the same area as the already busted levee, otherwise if the levee is by an area of NO not already flooded then there could be additional flooding. The real problem is the more levee failures the more levees that will need to be fixed before they can start pumping water out of the city

[arcticfire]

Well as I understand it unless a levee that holds the missippi back breaks it won't get any worse. Holding back the lake is mute when the city is flooded to the lake level already. The missippi side of it is higher as I understand it and could potentially if those gave way drown most the city. Especially if you consider that there would be no shortage of water comming down the river.

[sponger]

I wonder what the effect will be from the Mississippi draining? I would assume not to gmuch impact from the ohio River but alot rain fell in the South. Where is a good hydrologist when you need one.

[soonertwister]

If the full evacuation of New Orleans is in fact an attainable goal, and not a mythical vision uttered by people who aren't willing to enforce it, it won't make much difference if more sections fail.

But if significant numbers are not evacuated, the more parts of the levee that fail, the greater the risk of rapid water level rises risking the lives of the remaining residents.

But I really believe that those who manage to avoid being evacuated will be more than 80% fatalities inside of a couple of months.

[LSU2001]

I maybe wrong and I am sure to be corrected if I am but I will give it a try. Many of the levees around NOLA are low hurricane levees. These levees hold back storm surge or even an extra high tide. However the river levees are about 30-40 ft high and hold back extremly high river water every spring. THese levees actually have helped to spare the west bank as the ponchatrain water cannot get over them. If new levee breaks are occuring in areas other than 17th stree canal then the floooding could get worse though not in the areas already equalized with the lake. For instance on the opposite side of the 17th streed canal the ground is dry. there has been some flooding in Jefferson parish as a result of water finding its way around the defenses but by and large this area has not been flooded. If the levee were to break say directly across from the current breach then large parts of jefferson would flood until that area equalized with the height of the lake.

I hope I helped to explain this but the system in and around NOLA is extremly complex and right now is not functioning as designed.
TIm

[soonertwister]

Actually lsu, the reports I've seen indicate that most of Jefferson Parish has been flooded in the last 24 or 48 hours, and that many persons have fled to the West Bank (whatever that is) and the conditions there for those seeking refuge are quite dire.

[sponger]

Thanks Tim! I lived for 5 years and never had a clue!

[gofast]

I could be wrong, but when I watch those videos of the broken levees from today, it sure looks like the water is now flowing in the opposite direction. Watch closely when they show the close-ups and you can see that the water is flowing in the opposite direction of the way the levee gave way. I believe when I saw this, it was when they were showing the 17th Street Levee break. Maybe the reason the Corps is not rushing in there is that the water is actually draining back in to the canal from the flooded area???

[schmita]

And please someone tell us, how old are these levees?
irina

[LSU2001]

Actually lsu, the reports I've seen indicate that most of Jefferson Parish has been flooded in the last 24 or 48 hours, and that many persons have fled to the West Bank (whatever that is) and the conditions there for those seeking refuge are quite dire.

Maybe so but I was watching wwl a little while ago and they showed video directly across from the break and had Maestri on talking about it. That is where I heard that much of that area was not flooded yet. However I would imagine the most of Jefferson is flooded since Jefferson Parish includes Grand Isle and points in between.
TIm

[LSU2001]

I could be wrong, but when I watch those videos of the broken levees from today, it sure looks like the water is now flowing in the opposite direction. Watch closely when they show the close-ups and you can see that the water is flowing in the opposite direction of the way the levee gave way. I believe when I saw this, it was when they were showing the 17th Street Levee break. Maybe the reason the Corps is not rushing in there is that the water is actually draining back in to the canal from the flooded area???

The water may in fact change direction but I would think that this could be related to tidal action. Remember these are not normal floodwaters but basically a tidal lake has expanded its shores.
TIm

[jasons2k]

I maybe wrong and I am sure to be corrected if I am but I will give it a try. Many of the levees around NOLA are low hurricane levees. These levees hold back storm surge or even an extra high tide. However the river levees are about 30-40 ft high and hold back extremly high river water every spring. THese levees actually have helped to spare the west bank as the ponchatrain water cannot get over them. If new levee breaks are occuring in areas other than 17th stree canal then the floooding could get worse though not in the areas already equalized with the lake. For instance on the opposite side of the 17th streed canal the ground is dry. there has been some flooding in Jefferson parish as a result of water finding its way around the defenses but by and large this area has not been flooded. If the levee were to break say directly across from the current breach then large parts of jefferson would flood until that area equalized with the height of the lake.

I hope I helped to explain this but the system in and around NOLA is extremly complex and right now is not functioning as designed.
TIm

Thanks for that explanation. Now that makes me wonder - with the additional water in the city something that needs to be considered is the tremendous weight of that water. I wonder what kind of geological impacts of that now redistributed weight in the city will have on the remaining levee system. Not to mention the water itself is probably saturating and loosening what's left.

[LSU2001]

Actually lsu, the reports I've seen indicate that most of Jefferson Parish has been flooded in the last 24 or 48 hours, and that many persons have fled to the West Bank (whatever that is) and the conditions there for those seeking refuge are quite dire.

Maybe so but I was watching wwl a little while ago and they showed video directly across from the break and had Maestri on talking about it. That is where I heard that much of that area was not flooded yet. However I would imagine the most of Jefferson is flooded since Jefferson Parish includes Grand Isle and points in between.
TIm

Ps. the west bank is the west side of the mississippi river. They are moving folks over to that side by barges and ferrys now. I just heard that on WWL radio.
TIm