2019 Mississippi River

[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.

[Cajunrunner]

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

I blaming whatever mammal let out the first fart.

[CajunNation]

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.

If the ORCS failed, Morgan City would have 48 hours to evacuate, forever.

[cajun4life]

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.

Personally I could care less about oyster beds that weren’t originally there to begin with. Those beds were seeded in areas that were historically freshwater marsh. It’s time that they should be returned to freshwater marsh supplied by the river imo.

It will never happen though.

[Cajunrunner]

1973 was a significant event. They almost lost a wing wall for the low sill structure. Follow the link for a brief discussion of the ORCS Morganza complex.

http://www.americaswetlandresources....erControl.html

I drove through the Morganza complex in 2011. It was scary, the Mississippi river was wide, very very very wide. I would suspect that one day the Atchafalaya will eventually capture the Mississippi river one day as it is the shortest route to the Gulf of Mexico. (The energy grade line is steeper down the Atchafalaya than the Mississippi and the only thing in it's way is the ORCS)

this is a US Corps of Engineers link

https://www.mvn.usace.army.mil/Porta...olBrochure.pdf

During the Acadiana summer flood of 2016, we were driving back to Lafayette from Tennessee. The original plan was to head down through Mississippi and catch I-10. Then a portion of either I-55 or I-59 had collapsed, and there was flooding in the areas East of BR.

We only had to go back to Lafayette to get the family dog before heading back to Sugar Land the next day, so we debated leaving the dog another week, but then I decided we’d route through Natchez, Jonesville and Alex to I-49 to get us to Lafayette by midnight so I could sleep a bit.

Well...for some reason with it dark I got confused and took LA 15 South out of Ferriday and before I realized it, we were on along the Mississippi and too late to turn around without losing significant time, so I made sure to creep into any water that was on the road, and there was lots of patches of water.

Water wasn’t coming over the levee, but it was almost as if the force of the river was causing saturation through the ground and rising to the top along the roadway. We eventually made it down to Melville and Port Barre before getting on I-49. Vehicles parked at the welcome center at that exit were completely under water.

EDIT: Now that I decided to revisit a map, remember now that we did go West in LA 360 out of Bayou Current to Pametto, then through Lebeau to I49. Was quite an adventure that late at night knowing areas all around us were under water.

[Boomer]

Please BWK return with your input on the subject matter!