Will Katrina cause the Mississippi to change course?

[Silverhair]

For those that don't know, the lower Mississippi changes course about ever 400 years. At the time New Orleans was settled the river had just changed it's course. Now it is trying to change again and take a more direct, more southerly, route to the Gulf. The "Old River Control Structure"was built by the Corps of Engineers to stop that from happening.

When I was living in New Orleans in the late 70's the Engineers were warning that the structure had been weakened, could not be repaired, and that the Mississipppi would one day break free of the structure and take a new course, leaving New Orleans. They warned that the triggering event would likely be a really big flood.

I did some googling to see what I could find, but all I came up with on a short search said nothing about that.

Does anybody know much about this topic? If so, could Katrina cause the Mississippi to change course?

[Selatius]

1. The control structure would have to break apart in the storm

It's sort of like a dam. Once it goes, there's nothing that could contain that power. The Atchafalaya Basin sits lower now than the Mississippi River Basin. Water wants to flow down to the lowest point. One day, mother nature will win, and the Mississippi River will no longer flow by New Orleans.

Against mother nature there is no victory.

[DuckBurp]

11. The control structure is north of Baton Rouge

It doesn't seem that any storm surge from a huricane could go up the Mississippi River far enough north to affect it.

[Selatius]

12. No, one hurricane might not do it, but time certainly could

The River wants to go down the Atchafalaya Basin, not the Mississippi Basin. It can't be held back forever, and it will break free in due time.

[markus]

2. That would likely require such a catrastrophic backflow of the river

there's be nobody left downstream to care.

Someday, the Old River Control Structure will go. But I don't think this is it.

[TomInTib]

7. It wouldn't take much

The Mississippi has -south of St Louis- a very shallow catch basin.

[JHB]

3. If I were a Fox News anchor....

...my "first thought" would be checking real estate values around Morgan City. They might be on the rise if Katrina pulls a "worst case" on NO.

[ewagner]

6. Here's an example of Fox

talking about the hurricane earlier today.....this was taken off of another discussion board...(I have no idea who bastardi is)

Listening to Fox News...Shephard Smith on Bourbon St...stupid...at a bar that he said was packed full of people partying..stupid.

can they really not care/ignore/think nothing will happen?

Oh my bastardi is on as well...he must be hyped having his NO storm...I mean nothing bad that statement mods...those who watch/listen to him know what I mean

[JHB]

14. Is he staying with them?

One can only hope...

[ewagner]

15. Sounds like it

I can't bring myself to hit the channel.....I suspect that Charter Cable has some way of metering what channel I'm watching for marketing purposes....paranoid?

[JHB]

17. I wish I didn't know that...

...It's almost enough to make me wish Bad Things on NO, and it's never done me any harm...

[ewagner]

4. Wasn't the old change of course

triggered by an earthquake in Tennessee/Arkansas area?

I'm foggy about that...

[Silverhair]

10. Different course change. NT

[NYC]

5. Latest info. I could find.

August 8, 2005. Army Corps of Engineers:

On 10 August 2005, between the hours of 7:30 a.m. and 4:30 p.m., the U.S. Army Corps of Engineers will significantly increase the diversion of water through the Old River Control Structure. This diversion will increase the stage and velocity on the Atchafalaya River in the vicinity of Simmesport, Louisiana (and to lesser amounts downstream and upstream). These effects will occur between 10:30 a.m. and 8:30 p.m. Also, the draw through the Old River Control Structure (mile 311.4 AHP of the Mississippi River) will increase. Mariners should exercise extreme caution when navigating through these areas during the above-mentioned time period. EMILE F. SCHILLING III Chief, Operations Techincal Support Branch http://www.mvn.usace.army.mil/navbulletins/Detail.aspx?ID=136

Looks like that is all there is of a current nature.

General (interesting) article re floods on the Mississippi:
http://www.srh.noaa.gov/topics/attach/html/ssd98-9.htm

[El Supremo]

8. It could change course if...

there was a big rise in the river above the control. This would be more likely caused by heavy spring rains and runoff north of the lower Mississippi Basin. But if the storm was to sit over eastern Mississippi, it could happen. hat is not likely.

I'm not an expert. I just have a B.S. in Geophysics.

[madrchsod]

9. that was the first thing i thought about and posted about

this morning. if things go to hell, there is no way the midwest is going to get grain cheaply out of this country. there will be a critical shortage of petro by- products and natural gas in the midwest in the midwest there will be a huge economic disruption. there is a very good chance it will happen if conditions are bad enough.

[sam sarrha]

13. Yes it will... it will soon be flowing thru down town New Orleans..

[hootinholler]

16. Most likely yes...

It changes course all the time. In the late 1800s people would help it cut across a loop-back by digging a ditch and waiting for a flood.

Will it bypass N.O.? who knows, but that's an awful lot of water headed upstream. If if stalls before it hits the St. Lawrence basin or the Eastern Continental Divide, then guess where all that water drains.

WWL-tv had an expert who was talking about record stages on the Miss as the storm arrives. Folks, flood stages on the Mississippi have been measured for what, (my guess) 200 years?

I think that most of the delta could be underwater for 2-3 weeks. Once submerged, the channel will go where ever it wants to. I doubt seriously that the water in N.O. is going to suddenly dry up, but, it would be beneficial in the long term for the safety of the city if the main flow turned away from N.O.

-Hoot