2019 Mississippi River

[cajun4life]

Thanks. I'll read up on that.

Some is far fetched, but possible, I guess.

[mahtoo]

Some is far fetched, but possible, I guess.

Agree. I'm going to try to get some verification on what is stated in the article.

[angeleast]

From what I have read, the rate of flow is not swift enough above BR to scour the river. The Atchafalaya doesn’t have this problem as it has a relatively straight path to the GOM.

Just from the looks of what’s happening upriver (Midwest) I think we are in trouble if we continue to have high precipitation throughout the middle and lower miss river basin.

what is worst case scenario for course change which cities would be in danger

[HelmutVII]

From what I have read, the rate of flow is not swift enough above BR to scour the river. The Atchafalaya doesn't have this problem as it has a relatively straight path to the GOM.

Just from the looks of what's happening upriver (Midwest) I think we are in trouble if we continue to have high precipitation throughout the middle and lower miss river basin.

Correct, BUT once the lower reaches of the Mississippi river scour, the scour will work its way up stream. There could be a significant delta building event at the Mississippi river this year. Given the extreme wet weather that the upper Mississippi and Ohio river basins have had this winter any additional rainfall will just make the situation worse as the antecedent precipitation index is quite high righ now.

The Atchafalaya does not have the silt problems because the water supply is from the ORCS. The ORCS takes water from the upper levels of the Mississippi river. Most of the silt load is at the bottom of the river. (The Atchafalaya water is decant water from the Mississippi).

Going back in time we discover that the Atchafalaya was, at one time, the Mississippi river. The old Mississippi river deposited silt as it reached the Gulf of Mexico and built land until it made that course longer than its current course. That portion of Louisiana below Baton Rouge had not been formed yet because the river had not changed its course. In engineering terms the Atchafalaya is the "OLD RIVER" and that is why they call it the Old River Control Structure. From a hydraulic standpoint the Atchafalaya is a DISTRIBUTARY of the Mississippi river.

Going Further back in time the Bayou Teche was the course of the Mississippi River and the Vermilion River was a distributary of the then Mississippi river when it occupied the route of the Bayou Teche.

Go here https://www.nrcs.usda.gov/Internet/F./lafayette.pdf

and advance to page 13 of the PDF document and it will provide a very thorough discussion of the land forms of Lafayette Parish. Basically from the Coteau Ridge east are alluvial deposits of the Mississippi River and from the Coteau Ridge west are alluvial deposits of the Red River (believe it or not). Both depositions are from Pleistocene era which were later covered with loesse (wind borne) deposits. Examination of old quad maps of eastern Lafayette parish shows evidence of ancient Ox Bows and river scars The soil maps in the link above also indicate ancient OX Bows and river scars. These scars and ox bows are remnants of the ancient (Pleistocene era) locations of the Mississippi River.

One of the triggers for opening the Morganza spil way is the velocity of the water in the river. As the water gets higher and the velocity gets above 2 feet per second the scour gets to be aggressive. When the water gets up to the river side of the levees the levees start to scour (the grass rolls up into balls). In order to prevent that from happening they open the Morganza spill way.

[RaginCajun77]

From what I gather Morgan City and surrounding cities would be lost. It is highly likely that bridges that cross the Atchafalaya would be lost as well based on my reading. It would be a catastrophic event, pipelines lost, economy would suffer.

[angeleast]

From what I gather Morgan City and surrounding cities would be lost. It is highly likely that bridges that cross the Atchafalaya would be lost as well based on my reading. It would be a catastrophic event, pipelines lost, economy would suffer.

Freaking nightmare . the displaced people would be unimaginable

[HelmutVII]

what is worst case scenario for course change which cities would be in danger

New Orleans would not be able to support deep sea commerce trading and more importantly the entire city of new orleans and surrounding areas would not have a fresh water supply. The intakes to the water plant would still be under water but the water would be either brackish or full blown Gulf of Mexico salt water. The city of New Orleans water plant does not have the means to remove salt from water. This is significant. Baton Rouge gets its water from wells tapping the Baton Rouge Aquifer. However, over time there is a possibility that the aquifer could become brackish. Baton Rouge Water presently has scavenger wells to the south of their well fields to intercept brackish water infiltrating the Baton Rouge aquifer from the south. Baton rouge could not function as a deep water port either.

Morgan City and towns above and inside the basin would be in peril. Interstate 10, highway 190 and possibly highway 90 could be severed.

It would be a significant (almost cataclysmic) event should the Atchafalaya capture the Mississippi. Could it be reversed, probably, but it would take time and several boat loads of money. However, the environmental damage would be significant and would take a long time to reverse if at all. Unfortunately, we being humans, think that what is currently the situation is normal and should stay that way. However, in geologic time frames and perspectives we not even a follicle on the butt of time and we are insignificant. If the Mississippi River decides it's going to change course it damn well is going to do it and there is not much we can do about it. It has done it in the past and it will do it in the future. As Carl Sagen was so fond of saying "the laws of physics (nature) are universal and they cannot be broken".

[angeleast]

New Orleans would not be able to support deep sea commerce trading and more importantly the entire city of new orleans and surrounding areas would not have a fresh water supply. The intakes to the water plant would still be under water but the water would be either brackish or full blown Gulf of Mexico salt water. The city of New Orleans water plant does not have the means to remove salt from water. This is significant. Baton Rouge gets its water from wells tapping the Baton Rouge Aquifer. However, over time there is a possibility that the aquifer could become brackish. Baton Rouge Water presently has scavenger wells to the south of their well fields to intercept brackish water infiltrating the Baton Rouge aquifer from the south. Baton rouge could not function as a deep water port either.

Morgan City and towns above and inside the basin would be in peril. Interstate 10, highway 190 and possibly highway 90 could be severed.

It would be a significant (almost cataclysmic) event should the Atchafalaya capture the Mississippi. Could it be reversed, probably, but it would take time and several boat loads of money. However, the environmental damage would be significant and would take a long time to reverse if at all. Unfortunately, we being humans, think that what is currently the situation is normal and should stay that way. However, in geologic time frames and perspectives we not even a follicle on the butt of time and we are insignificant. If the Mississippi River decides it's going to change course it damn well is going to do it and there is not much we can do about it. It has done it in the past and it will do it in the future. As Carl Sagen was so fond of saying "the laws of physics (nature) are universal and the cannot be broken".

and we think we have problems now!!! However, lets hope the chances remain low. VERY LOW

[ZoomZoom]

While the silt is there, the general rule of thumb is that for every foot the water level rises a foot of the river bed is scoured and transported downstream. The Ohio river basin has had extreme rainfall this entire winter. This could be a repeat of 2011 or 1973. 1973 is when they almost lost the ORCS. They were throwing cars, railroad cars and BFR in the hole on the side of the structure to keep from losing it.

Had a roomie from Morganza. He remembers not only throwing anything they could at it but the military was out there heavily armed. They had orders to fire at will if anyone not authorized breached the area.

I got pictures from 2011 when they were making sand bags at Lebeau. That was Mother's day weekend. This is going to be very interesting.

As far as the Mississippi changing, as one geologist told me, it’s not if, it’s when. It’s documented the Mississippi has changed directions multiple times thru time. There is nothing mankind has done or can do to stop nature.

[RedTails]

Follow the link for a brief discussion of the ORCS Morganza complex.

http://www.americaswetlandresourceserControl.html

This article was fascinating, especially the book excerpt about what would have happened to South LA/US if it would have failed.

[ZoomZoom]

Well, whenever this happens, the race will be on for the new ports to replace BR and NO. Not only Mother Nature is in play, our enemies surely know kill transportation on the Mississippi, cripple America.

[cajun4life]

Correct, BUT once the lower reaches of the Mississippi river scour, the scour will work its way up stream. There could be a significant delta building event at the Mississippi river this year. Given the extreme wet weather that the upper Mississippi and Ohio river basins have had this winter any additional rainfall will just make the situation worse as the antecedent precipitation index is quite high righ now.

The Atchafalaya does not have the silt problems because the water supply is from the ORCS. The ORCS takes water from the upper levels of the Mississippi river. Most of the silt load is at the bottom of the river. (The Atchafalaya water is decant water from the Mississippi).

Going back in time we discover that the Atchafalaya was, at one time, the Mississippi river. The old Mississippi river deposited silt as it reached the Gulf of Mexico and built land until it made that course longer than its current course. That portion of Louisiana below Baton Rouge had not been formed yet because the river had not changed its course. In engineering terms the Atchafalaya is the "OLD RIVER" and that is why they call it the Old River Control Structure. From a hydraulic standpoint the Atchafalaya is a DISTRIBUTARY of the Mississippi river.

Going Further back in time the Bayou Teche was the course of the Mississippi River and the Vermilion River was a distributary of the then Mississippi river when it occupied the route of the Bayou Teche.

Go here https://www.nrcs.usda.gov/Internet/F./lafayette.pdf

and advance to page 13 of the PDF document and it will provide a very thorough discussion of the land forms of Lafayette Parish. Basically from the Coteau Ridge east are alluvial deposits of the Mississippi River and from the Coteau Ridge west are alluvial deposits of the Red River (believe it or not). Both depositions are from Pleistocene era which were later covered with loesse (wind borne) deposits. Examination of old quad maps of eastern Lafayette parish shows evidence of ancient Ox Bows and river scars The soil maps in the link above also indicate ancient OX Bows and river scars. These scars and ox bows are remnants of the ancient (Pleistocene era) locations of the Mississippi River.

One of the triggers for opening the Morganza spil way is the velocity of the water in the river. As the water gets higher and the velocity gets above 2 feet per second the scour gets to be aggressive. When the water gets up to the river side of the levees the levees start to scour (the grass rolls up into balls). In order to prevent that from happening they open the Morganza spill way.

Currently the only landmass gain in Louisiana is in the Atchafalaya Delta. It’s gaining land at a pretty high rate.

If the COE would blow the levee below Braitgwaite and allow the lower delta to replenish the marsh south and southwest of Nola it might help build our coast and prevent catastrophic flooding.

[ZoomZoom]

Erosion has been around a long time before the cumbustion engine. It's the caveman's fault, he learned to start a fire.

[HelmutVII]

Currently the only landmass gain in Louisiana is in the Atchafalaya Delta. It's gaining land at a pretty high rate.

If the COE would blow the levee below Braitgwaite and allow the lower delta to replenish the marsh south and southwest of Nola it might help build our coast and prevent catastrophic flooding.

Follow this link

http://mississippiriverdelta.org/wha.l-restoration/

You might want to read this research paper. you will have to go through the usual process to download.

https://www.academia.edu/15232325/Ex.tern_Louisiana

One of the issues involves is the Oyster beds south of New Orleans. Too much sediment kills the oyster habitat.

[HelmutVII]

Erosion has been around a long time before the cumbustion engine. It's the caveman's fault, he learned to start a fire.

Subsidence is a significant if not the most significant cause of coastal erosion.