2019 Mississippi River

[Cajun90]

With the likely opening of the ORCS and Morgansa Spillway, is everyone out of the floodplain?

Last I heard the Corps said there are no expectations at this time open the Morganza.

[Cajun90]

Good read on the Morganza

https://www.wunderground.com/blog/Je.ontrol-st.html

[cajun4life]

Last I heard the Corps said there are no expectations at this time open the Morganza.

While that is currently the plan, Tennessee and Arkansas are continuing to get hammered with rain and have severe flooding now. Also the Miss River has silted in an incredible 30’ between ORCS and BR since 2011.

I’d be shocked if they don’t open all flood control structures in some fashion.

[HelmutVII]

Mississippi River at Knox Landing

https://waterdata.usgs.gov/la/nwis/u.20,63160,00060

Mississippi River at Baton Rouge

https://waterdata.usgs.gov/la/nwis/u.20,63160,00060


Mississippi River at Bonnet Carre

https://waterdata.usgs.gov/la/nwis/u.20,63160,00060

Gage heights at all three locations are on the same datum.

[HelmutVII]

While that is currently the plan, Tennessee and Arkansas are continuing to get hammered with rain and have severe flooding now. Also the Miss River has silted in an incredible 30’ between ORCS and BR since 2011.

I’d be shocked if they don’t open all flood control structures in some fashion.

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.

[RedTails]

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.

ORCS - Old River Control Structure if anyone wants to learn something like I did today. Didn't recognize that acronym.

Trying to visualize what happened in 1973 (haven't heard that story). What part of the structure were they doing that to? Overbank, low sill, auxiliary? Very interesting stuff, thanks Helmut.

Edit: Just getting around to clicking Cajun90's link. Thanks for that

[HelmutVII]

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.americaswetlandresourceserControl.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

[RedTails]

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.americaswetlandresourceserControl.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

Gonna read on that when I get home. Thanks!

[Cajun90]

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.americaswetlandresourceserControl.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

It has been many years ago since I heard this but was once told that if they lost the Morganza structure it would probably be a non recoverable event. In this day and age of technology I find that difficult to believe but it certainly underscores how bad a scenario we are talking about.

[mahtoo]

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.americaswetlandresourceserControl.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

The south east (south end of the structure on the river side) wing wall was lost.

[mahtoo]

While that is currently the plan, Tennessee and Arkansas are continuing to get hammered with rain and have severe flooding now. Also the Miss River has silted in an incredible 30' between ORCS and BR since 2011.

I'd be shocked if they don't open all flood control structures in some fashion.

I am curious as to where the 30' siltation figure comes from.

[cajun4life]

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.

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.

[cajun4life]

I am curious as to where the 30' siltation figure comes from.

https://www.workboat.com/news/coasta.course-change/

[cajun4life]

https://www.workboat.com/news/coasta.course-change/

I am curious as to where the 30' siltation figure comes from.

[mahtoo]

https://www.workboat.com/news/coasta.course-change/

Thanks. I'll read up on that.