2011 Mississippi River Spring Floods

[jumboragncajun]

http://www.mvn.usace.army.mil/bcarre/morganza.asp

Helumt, why if gates are closed did discharge rate go up?

CharlieK, an article on KATC's website explains it. When they measured the flow with 17 bays open, it actually measured at 170k cfs, not the 114k they were expecting. They closed three bays and reduced to 140,000 cfs.

I have been following the project flood charts daily for the last month. Since Morganza opened there have been some minor discrepancies with the Qin and Qout summations. Qin being flow from Natchez and Qout being ORCS, Morganza, and flow at BR. So they estimate being
Off did not surprise me.

igeaux.mobi

[HelmutVII]

_ You're damn right I have a motive for wanting those gates closed ASAP. If you don't have one then you're touched in the head mister. So you don't feel sympathy for people who make thier livings in the basin. Do you have sympathy for the people down stream of the levee system who will be staring down the barrel of a loaded gun for another 5-6 weeks in your scenario? How about the thousands of animals who will be killed by your scenario? You got any sympathy for them?

What about South Lafayette? The scenario I posted back to Turbine is absolutely the most dangerous one of all the scenarios in this little drama. On June 27th, 1957 the lower Atchafalaya was still high due to drain off from winter snow & spring rain. When Hurricane Audrey hit land in Grand Chenier it has been reclassified as a Cat. 4 storm, but the maximum clocked wind speed was 105 MPH. This made her in reality a Cat. 2 hurricane. Where do you think the 20+' strorm surge that made Audrey such a killer came from?

Would you have any sympathy for the people who would have 4-10' of water in their houses & the 400,000 or so people that would be displaced if a Cat. 3 hurricane made landfall a month early between Morgan City & Cameron? Or should they have known not to live in the city of Lafayette even though the odds of this happening are 1 in 50? _

Well actually no I don't. They make a good living when things like this don't happen but they take a gamble every year and most times they win. This year they didn't. They know they are taking a chance but they do it anyway. So far as the people down there subject to flooding I ask them "why do you live in an area that floods so much." They get flooded with things like this and with hurricane storm surge. after a while you would think they would get tired of it. As far as the animals, I think they are handling the situation alot better than you are. The basin is a hydraulic capacitance and nothing more. We get the benefit of recreation and natural resources from it solely from the grace of God.

So far as the Hurricane matter, this is what i think you should do. Go to New Orleans and request time to address the New Orleans City council. Tell them you want to enlist their support to petition the Corps of engineers to close all the Morganza flood gates ASAP. Then tell them you are concerned about the potential for a hurricane causing a storm surge of up to 27.0 feet MSL up the Atchafalaya Basin. Not only that, a buddy of mine had to shut down his business because of the high water. Do you think they will say "why thank you Mr King we did not realize all of this and we are certainly sorry for any problems this situation may have caused you. As a matter of fact, we are so stupid to not think of it ourselves. Please leave your name and number with the clerk so we can contact you as soon as we have contacted the Corps of engineers". I really don't think that would happen, they would probably call Marie and put a Gris Gris on you that would result in every well you drilled for the rest of your life being drier than a popcorn fart. Can you imagine that --- lets put more water down to New Orleans with Hurricane season coming and they are at flood stage down there from now to as far as they can make predictions. Yeah that's the ticket ----they can really handle floods on the Mississippi PLUS a storm surge from a Hurricane. Absolutely brilliant. I think you should take your medication.

[Turbine]

I have sympathy for anyone who experiences unfortunate/unforeseen occurrences.

At some point in time they befall us all.

If those who live and conduct business in the Basin should have known better, then they are no the only one who should have known better. Perhaps the area should have been made off limits for human habitation.

[HelmutVII]

_ http://www.mvn.usace.army.mil/bcarre/morganza.asp

Helumt, why if gates are closed did discharge rate go up? _

I read this article

http://www.2theadvocate.com/news/lat...-cut-flow.html

in the Advocate this morning saying they were passing 172K CFS. Everything I read prior to that said they were passing 114K CFS. (I always thought that that figure was kind of low. a big gate like they have up there should pass more than 6700 CFS) I went to your link and noticed the numbers didn't make sense and I figured an error was made. They closed two more today and are still passing 120K CFS. through 12 gates or 10,000 CFS per gate which is more like it.

The second page of the article gives a good explaination of how they measure velocity and get cross sections. The last two paragraphs gloss over the 1.5 Million CFS limit. If you go back to post 381 where I gave a link to Mannings equation you will see a reference to "n" in the equation. That is the roughness coefficient. The "n" for the grass on the levees is different than the "n' for the mud in the river. With the water moving faster for higher flow rates the interaction with the grass on the levees would cause a shear at the interface between the water and the levee. The river would literally tear the grass off the levees that could cause scour damage. This along with several other factors is the reason for the 1.5 million CFS limit.

[CharlieK]

_ I read this article

http://www.2theadvocate.com/news/lat...-cut-flow.html

in the Advocate this morning saying they were passing 172K CFS. Everything I read prior to that said they were passing 114K CFS. (I always thought that that figure was kind of low. a big gate like they have up there should pass more than 6700 CFS) I went to your link and noticed the numbers didn't make sense and I figured an error was made. They closed two more today and are still passing 120K CFS. through 12 gates or 10,000 CFS per gate which is more like it.

The second page of the article gives a good explaination of how they measure velocity and get cross sections. The last two paragraphs gloss over the 1.5 Million CFS limit. If you go back to post 381 where I gave a link to Mannings equation you will see a reference to "n" in the equation. That is the roughness coefficient. The "n" for the grass on the levees is different than the "n' for the mud in the river. With the water moving faster for higher flow rates the interaction with the grass on the levees would cause a shear at the interface between the water and the levee. The river would literally tear the grass off the levees that could cause scour damage. This along with several other factors is the reason for the 1.5 million CFS limit. _

Thanks helmut and jumbo.....makes sense now.

[Chop]

This is one of those subjects that I have no knowledge about.
So it would be foolish of me to take sides on who is right and who is wrong.

I know Kyle is a pretty smart guy, but I would never go against someone who does this for a living unless I really knew what I was talking about.

So im not picking sides on this.

I will say kyle's predictions on what was going to happen were pretty much 100% accurate.

But I dont have the knowledge to know if it was because Kyle knows what he is talking about or if its just a wild coincidence.


Kyle may be on to something on one hand, but on the other hand maybe not.

It may be like saying three 4th of July's ago I was popping fireworks and it started raining, so this must mean that popping fireworks causes rain. LOL

Or maybe Kyle really is onto something. I am not willing to go to school for four years to give an educated opinion on this subject.


One thing is for sure, a lot of people learned a lot info because of the questions and statements made by Kyle.

I learned a few things in this thread, but not enough to give insight on who is wrong or right.

[jumboragncajun]

One thing I have maintained throughout this discussion is that the reduction of stage level did not automatically mean reduction in flow. It possibly COULD, but other things needed to be checked before making that definitive statement. Attached to this link are hydrographs for the Stage, Velocity, and Discharge of the Vermilion River at Surrey St for the last 3 days. In this particular case, when the stage lowers, the concurrent velocity hydrograph is almost perfectly INVERSELY related. Then, it is very obvious that the velocity and Discharge Hydrographs are DIRECTLY related. So, as you can see, where the river dropped a half foot, in that EXACT TIME, the flow rate has nearly doubled. Yes, twice the amount of water flowing under the Surrey St Bridge as the river has dropped.


http://nwis.waterdata.usgs.gov/la/nw...te_no=07386880

[CharlieK]

_ This is one of those subjects that I have no knowledge about.
So it would be foolish of me to take sides on who is right and who is wrong.

I know Kyle is a pretty smart guy, but I would never go against someone who does this for a living unless I really knew what I was talking about.

So im not picking sides on this.

I will say kyle's predictions on what was going to happen were pretty much 100% accurate.

But I dont have the knowledge to know if it was because Kyle knows what he is talking about or if its just a wild coincidence.


Kyle may be on to something on one hand, but on the other hand maybe not.

It may be like saying three 4th of July's ago I was popping fireworks and it started raining, so this must mean that popping fireworks causes rain. LOL

Or maybe Kyle really is onto something. I am not willing to go to school for four years to give an educated opinion on this subject.


One thing is for sure, a lot of people learned a lot info because of the questions and statements made by Kyle.

I learned a few things in this thread, but not enough to give insight on who is wrong or right. _

BWK made a bunch of completely incorrect statements as well. If you throw enough crap against the wall some will stick.

[NewsCopy]

  The Army Corps of Engineers has closed five bays at Morganza since Tuesday as the river’s flow rate drops, corps spokeswoman Rachel Rodi said Thursday.

No bays have been closed on the Bonnet Carre Spillway because “the water is slowing down on its own,” said Rodi, although she declined to rule out the possibility of closings there.

The rest of the story

[NewsCopy]

Satellite images show large amounts of sediment throughout coastal Louisiana as a result of flooding on the ... to a request by the USGS National Wetlands Research Center in Lafayette, La. This is part of an ongoing commitment by NASA’s Applied Science ...

The rest of the story