2011 Mississippi River Spring Floods

[Bandwagon King]

_ I thought there was something called structural design capacity. This is not to say it couldn’t handle more than its STC, only that the results of going over, could not be sustained indefinitely.

What am I missing here? _

When a structure like that is designed the area of the structure is the basis for figuring the amount of fluid that will go through it. The hydraulic head will have a small effect, but you can't put more than the square footage of the of openeing will allow per second. Factors that are not take into account, but have a definite affect on calculating flow rates through that structure are friction & oxidation of the water as it passes through.

The reason the water foams up when it is coming through a differential structure like that is from the water oxidizing. The greater the pressure the more the oxidation. There is also friction tension which takes place as water passes through the control structure. These account for small percentages of the overall flow , but take away from the CFS the structure is handling to begin with. The greater the head, the higher the differential, & the greater the area of flow, the more these factors are present.

That is why the only true way to figure volumes is by positive displacement. There is no controlled way to figure either of these since the factors change every second. You can make an educated guess & its a darn good one about what will happen by these calculations, but the levels tell you if you are overcoming the feed from upstream or not, better than anything else. That is why they are so important. They provide with certainty that you are either getting rid of water faster than it is coming to you or not.

I didn't want to get into this stuff & left it alone although I knew this days ago. It is part of every engineering equation for my industry as much as Velocity X Area would be.

[CharlieK]

_ When a structure like that is designed the area of the structure is the basis for figuring the amount of fluid that will go through it. The hydraulic head will have a small effect, but you can't put more than the square footage of the of openeing will allow per second. Factors that are not take into account, but have a definite affect on calculating flow rates through that structure are friction & oxidation of the water as it passes through.

The reason the water foams up when it is coming through a differential structure like that is from the water oxidizing. The greater the pressure the more the oxidation. There is also friction tension which takes place as water passes through the control structure. These account for small percentages of the overall flow , but take away from the CFS the structure is handling to begin with. The greater the head, the higher the differential, & the greater the area of flow, the more these factors are present.

That is why the only true way to figure volumes is by positive displacement. There is no controlled way to figure either of these since the factors change every second. You can make an educated guess & its a darn good one about what will happen by these calculations, but the levels tell you if you are overcoming the feed from upstream or not, better than anything else. That is why they are so important. They provide with certainty that you are either getting rid of water faster than it is coming to you or not.

I didn't want to get into this stuff & left it alone although I knew this days ago. It is part of every engineering equation for my industry as much as Velocity X Area would be. _

You are simply wrong. The old river control structure flowed more than it's design capacity during the 1973 flood. That is a not my opinion, it happened. This damaged the structure, almost to the point of failure. This is not my opinon, it is published fact. You can choose to believe the sky is not blue, but that doesn't make it so.

Read page 5 of this report (page 11 of the PDF file).

http://www.lwrri.lsu.edu/downloads/L..._B12B_1980.pdf

The structure flowed 500,000 cfs instead of the designed 325,000 during the 1973 flood.

YOU ARE WRONG.

[Bandwagon King]

_ You are simply wrong. The old river control structure flowed more than it's design capacity during the 1973 flood. That is a not my opinion, it happened. This damaged the structure, almost to the point of failure. This is not my opinon, it is published fact. You can choose to believe the sky is not blue, but that doesn't make it so.

Read page 5 of this report (page 11 of the PDF file).

http://www.lwrri.lsu.edu/downloads/L..._B12B_1980.pdf

The structure flowed 500,000 cfs instead of the designed 320,000 during the 1973 flood.

YOU ARE WRONG. _

If it was flowing more than its design capacity, then the water was either going under over or around the calculated opening of the gates of the structure. I understand that you are saying that the calculated flow rates were above what it was designed to handle, however the given area of flow will only allow so much water through it. This will change slightly based upon the hydrostatic, hydraulic, or hydrodynamic head, "slightly", but once you are putting 10'X10' or 1000' X 1000' of solid fluid through a structure at a certain point you can't put anymore. That's it, cetu' fine'. I can't say I have seen the ORCS, although I have seen the power plant at Simmsport. I can say that structure is set up so that no more than a certain amount of water can flow through it no matter what. It appears as though it is about 30' thick of concrete & reenforced steel as I recall.

[CharlieK]

_ If it was flowing more than its design capacity, then the water was either going under over or around the calculated opening of the gates of the structure. I understand that you are saying that the calculated flow rates were above what it was designed to handle, however the given area of flow will only allow so much water through it. This will change slightly based upon the hydrostatic, hydraulic, or hydrodynamic head, "slightly", but once you are putting 10'X10' or 1000' X 1000' of solid fluid through a structure at a certain point you can't put anymore. That's it, cetu' fine'. I can't say I have seen the ORCS, although I have seen the power plant at Simmsport. I can say that structure is set up so that no more than a certain amount of water can flow through it no matter what. It appears as though it is about 30' thick of concrete & reenforced steel as I recall. _

Read the report, educate yourself, and stop thinking the river is a drilling rig. It is goverened by the rules of open channel flow which are different. The river has the power to make the path bigger.

And it WAS flowing more than it's capacity, it is not an IF. Again this is not my opinion it is a fact. Go ahead admit you were wrong, it will feel good.

[Bandwagon King]

_ Read the report, educate yourself, and stop thinking the river is a drilling rig. It is goverened by the rules of open channel flow which are different. The river has the power to make the path bigger.

And it WAS flowing more than it's capacity, it is not an IF. Again this is not my opinion it is a fact. Go ahead admit you were wrong, it will feel good. _

I am not saying the river did not flow more than its design capacity then. What I am saying is that for it to do so it had to suffer structural damage first. Then the flow rate went above the design for the structure. I don't know because I wasn't there, but I can tell you for a fact if it flowed more than 100% of the design it lost its integrity first & started leaking in places it shouldn't have. They have had 38 years to address this problem & fix & reenforce the structure to not allow it to happen again. You are telling me the egg came first. I got news. There aint no egg with out a chicken to lay it.

[CharlieK]

Great quote:

It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so.
-Mark Twain

And all of this is one of the main reasons the core watches the FLOW RATE so closely, so as to not destroy the structure keeping the Mississippi river in it's current channel.

But you keep watching river stages and the pressure on the Hydrill and keep us informed......

[jumboragncajun]

_ Read the report, educate yourself, and stop thinking the river is a drilling rig. It is goverened by the rules of open channel flow which are different. The river has the power to make the path bigger.

And it WAS flowing more than it's capacity, it is not an IF. Again this is not my opinion it is a fact. Go ahead admit you were wrong, it will feel good. _

It's no use people!

You can tell him that "design capacity" does not mean "actual capacity" and he will FIND a way to argue it. If you do convince him, he will start the "that's what I have been trying to say all along" statements....or or "once again I've just misspoken, that's not what I really meant" statements....'I knew this already but just didn't mention it' statements....

[Boomer]

CALLING DR. ZAPPI---CALLING DR. ZAPPI----------Man he should have all the kids monitoring this thread----What great info!!!! I feel like I am reading a historical novel before the fact---Kinda Like Rising Tide before it was written and the facts coming out ---keep the discussion going!!!!!! BTW---We should have a little pool on who is correct in their prognostications!!!!

[Bandwagon King]

_ It's no use people!

You can tell him that "design capacity" does not mean "actual capacity" and he will FIND a way to argue it. If you do convince him, he will start the "that's what I have been trying to say all along" statements....or or "once again I've just misspoken, that's not what I really meant" statements....'I knew this already but just didn't mention it' statements.... _

Ok, here's your chance to educate me. I have never read anything concerning the near loss of the ORCS. The knowledge I have is from someone who was there first hand. According to what this person told me, the structure started being undermined from underneath & started washing out below the gates. This caused the structure to lose control of the flow & it to release water at a way higher rate than the actual gates themselves were designed to release. He told me they were hauling in tons of rock & even sank barges in front of the structure to keep the structure from being completely undermined & washing away. Is this a correct accounting or not? I am asking for any corrections you can give me.

As for making a misstatement you may wish to interpret that as a self correction. If you have a problem with that then you are saying that even if I admit that I have not stated something right then I still have too much pride to correct myself, yet you attack me when I do correct myself. In that case there is no reasoning with you sir. If Mr./ Dr. / Prof. Helmut is correct in his theory on flow rates, I will gladly state so on this site. As a point of discussion he is most likely correct just not to the degree stated. The difference is you are flowing a 1/2 mile wide body of water into a 17 mile wide body of water. As you displace the higher level with land, less height, & less width & drain it into a resevoir that continues to increase in area as the height comes up, you will at some point reach a swap where the river will go down at as high, then higher, then much higher rate than the resevoir will come up.

As of this point, looking at the level in Baton Rouge going down now at the same rate that it is coming up in Butte Larose, I would respectfully disagree that more gates should be or need to be open. This would simply exasterbate a problem which appears totally avoidable at this time.

[CharlieK]

They will open more gates if the flow rates dictate it. Period. None of what you are saying is relavent to why they open the gates or not.