Re: Mississippi River Spring Floods of 2011
I agree with Bandwagon King in starting to close the gates. I know who he is, and he told me over a week ago that this rise would be much lower than predicted and listed many a good reason. He was right as he is right now. Pinching off on the downflow would give the lower flow a chance to start evacuating now. Why wait when you don't have to? Having worked in the oilfield and understanding flow control, this just amounts to a giant well and should be handled as such. When you have the "capacity" to control the flow PROPERLY, that is what you should do. This truly comes out to simple fluid "dynamics". You control your downstream flow by controlling your upstream flow WHEN YOU CAN, and in this case, you can because now you see what your projected volume is more clearly. It's kinda like the federal budget, you don't have people not paying enough tax, you have too many people SPENDING too much. Choke off the spending, the rest will take care of itself.
Re: Mississippi River Spring Floods of 2011
Quote:
Originally Posted by
biged05
_ I think Cajun_civil is right. One day mother nature will win again. You can't fight it forever. It might take a couple of major events to happen at once, but I think it will one day. I think one is to have high water and the New Madrid fault shifts and there's a major earthquake that would crumble levees and changes the coarse of the river. _
I am of the opinion (for the little it's worth) that it won't take anything as drastic as an earthquake, though that would surely get it done. It seems like a flood maybe 25% or more larger than the one we are seeing now, that occurs at a time when we haven't been seeing a drought here would do it. It seems like the flows throught the structures are always more than anticipated for the level of flood being handled. Not a knock on anyone, just a fact of life when dealing with an ever changing set of inputs. I think taking the long view our time to enjoy the Basin as a swamp is limited. This was inevitable from the day they cleared the log raft blocking the Atchafalaya in the 1800's. Unfortunatley while a lot has been done to try to stop it from happening, it does not appear much has been done to prepare for the inevitable day the river changes course. This event will leave NO and Baton rouge on a saltwater estuary with little to no freshwater to drink or use for industrial uses. It will destroy Morgan City and possibly flood other towns along the Teche Ridge (the natural boundary of the basin). It's seems like this is generally accepted as something that WILL happen, yet no one is prepared.
There are two ways New Orleans will be destroyed by a major flood, either too much fresh water or too little. Seems we are on top of one of them.
Re: Mississippi River Spring Floods of 2011
Quote:
Originally Posted by
charliek
_ Biged, Helmut, Civil.....I had heard somewhere but can't find it that it is some engineers opinion that the structure (the original low sill and overbank) were put in a less than optimum spot in the river. They stated that this was done for economic reasons. Not much else was explained. Is this based on it being on the inside bend of the river and if so why would this be less than optimum? _
From the book I'm reading-Designing the Bayous-referenced above in thread-they did not mention any of that. Accoring to the author-They studied looking for the optimum location and by Knox Landing they discovered an abandoned river channel about 2400 feet wide that ran nearly perpendicular to the Miss River that had various advantages. What's also interesting-like someone said about being pre-computer engineers with pencils-is that Albert Einstein's son, Frans, was involved in the design (he was a professor of hydraulic engineering). Also-at the time they were more concerned about moving as much sediment through the structure as possible. Also-when they had the problems in 1973 the south guide wall on the inflow side started moving-for some reason-probably to save $ they had not driven pilings mto support it as they had for most of the other parts of the structure
Re: Mississippi River Spring Floods of 2011
Quote:
Originally Posted by
LsuULfan
_ From the book I'm reading-Designing the Bayous-referenced above in thread-they did not mention any of that. Accoring to the author-They studied looking for the optimum location and by Knox Landing they discovered an abandoned river channel about 2400 feet wide that ran nearly perpendicular to the Miss River that had various advantages. What's also interesting-like someone said about being pre-computer engineers with pencils-is that Albert Einstein's son, Frans, was involved in the design (he was a professor of hydraulic engineering). Also-at the time they were more concerned about moving as much sediment through the structure as possible. Also-when they had the problems in 1973 the south guide wall on the inflow side started moving-for some reason-probably to save $ they had not driven pilings mto support it as they had for most of the other parts of the structure _
Oh I don't think that is the only way either. There are a lot of senerios that could make this take place. I've also heard that if there was more snow fall up north than in '73-'73 it would be a good possiblity. How about if there is that much snow fall, then we get rains like we did this year right after. Geez, that would be an insane amount of water comeing down here.
Re: Mississippi River Spring Floods of 2011
Quote:
Originally Posted by
capitalcajun
_ I agree with Bandwagon King in starting to close the gates. I know who he is, and he told me over a week ago that this rise would be much lower than predicted and listed many a good reason. He was right as he is right now. Pinching off on the downflow would give the lower flow a chance to start evacuating now. Having worked in the oilfield and understanding flow control, this just amounts to a giant well and should be handled as such.
Good lord. I think the corps needs to step out of the way and let the oilfield hands, i.e. "self proclaimed engineers" take over the control structures. Then we can get people from the NASA control room and let them take over offshore drilling. They can read graphs and punch buttons. I mean it is that simple, right BK.
Re: Mississippi River Spring Floods of 2011
Quote:
Originally Posted by
LsuULfan
_ From the book I'm reading-Designing the Bayous-referenced above in thread-they did not mention any of that. Accoring to the author-They studied looking for the optimum location and by Knox Landing they discovered an abandoned river channel about 2400 feet wide that ran nearly perpendicular to the Miss River that had various advantages. What's also interesting-like someone said about being pre-computer engineers with pencils-is that Albert Einstein's son, Frans, was involved in the design (he was a professor of hydraulic engineering). Also-at the time they were more concerned about moving as much sediment through the structure as possible. Also-when they had the problems in 1973 the south guide wall on the inflow side started moving-for some reason-probably to save $ they had not driven pilings mto support it as they had for most of the other parts of the structure _
I am reading that book now as well, but havn't gotten to that section. It is a good book so far. However remember it is written bya corp historian I believe. I will look in the other books I have and try to find where the question about the location came from. Sounds like from what you said here they chose it for ease of digging (existing channel). That would jibe with the comment of less than optimal as the existing channel may not have led to the structure being placed relative to the river in the best hydraulic position. Civil cajun mentioned the relative location of the aux structure being chosen to help support the low sill structure, maybe that was in response to this weakness in chosen location.
This is interesting stuff, till you think about the consequences of the inevitable failure.
Re: Mississippi River Spring Floods of 2011
Quote:
Originally Posted by
HelmutVII
_ I don't know the exact operating plan but I would suspect that they wouldn't think of closure until the total flow through all structures results in less than 1.5 million cfs at Red river landing including the normal 70/30 split at ORCS. into late June or early July.
I agree 100%. The outlet capacity at the GOM is estimated to be 1,250,000 cfs. More than that, the levees in New Orleans is at severe risk. With Bonnet Carré discharging 250k cfs, the magic 1,500,000 cfs trigger in Baton Rouge is attained. When the flow at Red River Landing is determined to be 1,494,000 cfs, I think CONSIDERATION will be given to closing 1 bay. When 1,488,000 cfs passess RRL, consideration will be given to closing 2 bays....etc etc.... unitl THAT happens, the "basin" will serve it's intended purpose and remain a "basin".
The latest flows at RRL were determined to be nearly 1.6 million cfs. (48 hours ago). So, not just yet.
Re: Mississippi River Spring Floods of 2011
Quote:
Originally Posted by
Turbine
_ The south wind of the last couple days has canals south of Abbeville full to the brim, with flooding in some low lying cattle pastures.
With all the extra water in the gulf I wonder how long it takes to dissipate. If it takes days for the water to get from the locks to Morgan City, it must take weeks and weeks to get out of the Gulf.
I hope we get a late hurricane season, I could see an early hurricane creating a serious storm surge pushing all that water back on land. _
Turbine, I wish to post this information to you & any other open minded knowledge seeking people who may be out there in the minority listening to me. When you & Chop who posted right underneath you on this subject, I was evasive. I did not want to think about it, but since then I have thought about it.
There are those who want to keep flooding the basin more than necessary just because they look at it as a drainage ditch, sewer system, whatever. I can tell you why you are absolutely 100% correct in your assessment of the potential danger in this situation & why we should be getting rid of this water into the GOM as fast as possible & not letting it remain in the basin any longer than it has to.
My earlier reply to your post was conditions were not favorable for an anitcyclonic build up in the GOM right now. That does not mean they can not be favorable somewhere else.
If a Cat.3 storm were to strike anywhere between the Sabine river & the mouth of the Atchafalaya within the next month the results WOULD be catastrophic. A storm surge that would normally stop somewhere around Hwy 14 could potentially be pushed up above I-10 & certainly would be pushed up as far as Hwy. 90. where the train tracks run. The only people who would be spared flooding to their homes are people who live along Couteau Ridge as well as any other elevations above I'd estimate somewhere around 27' above MSL.
The river is flowing all its water to the west now when it gets into the bays & marshes. Those bays & marshes are swelling & will continue to stay swollen unless the water is evacuated ASAP. The fastest way to do this is DOWN THE RIVER. Every inch the water goes up in the Basin is another 3-4 days it will take to get the Atchafalaya level back closer to normal. As it gets closer to normal the blessed flow rate slows down & allows it to evacuate to the GOM without backing up nearly as much. Since they have sunk the barge into Bayou Shane the river is now acting like a syphon & causing the levels in Bayou Shane Lake Polurde & points north & east to actually drop in level.
This means all the water being evacuated out of the Atchafalaya is coming west into lower west St. Mary, Iberia, Vermillion, & so on to the west all the way to the state line. The Intracoastal canal as well as other waterways will attempt to distribute the water, but the longer this situation keeps up the more danger we are in. Before any self seving brain surgeons on here tell me how wack I am, you better check your ego at the door. Don't tell me it can't happen this way, because it already has happened this way. Has anyone ever heard of Hurrican Audrey? Check your callender & tell me it can't happen.
For those folks who told me I need to look at the big picture, my response would be look at the BIG, BIG picture. If there is 0.0001 per cent chance of this happening, we better be doing all we can to avoid the scenario. That is unless you want the SWAMP to take on a whole new meaning.
Re: Mississippi River Spring Floods of 2011
Quote:
Originally Posted by
Bandwagon King
_ The only people who would be spared flooding to their homes are people who live along Couteau Ridge as well as any other elevations above I'd estimate somewhere around 27' above MSL.
Check your calculations, mine say 27.38625' above MSL. But that's only if Dexter Aucoin is kicked off the team. Otherwise the collective mass of Cajuns exhaling in relief would force the water back down to around 25.375852'
Re: Mississippi River Spring Floods of 2011
Quote:
Originally Posted by
Bandwagon King
_ If a Cat.3 storm were to strike anywhere between the Sabine river & the mouth of the Atchafalaya within the next month the results WOULD be catastrophic. A storm surge that would normally stop somewhere around Hwy 14 could potentially be pushed up above I-10 & certainly would be pushed up as far as Hwy. 90. where the train tracks run. The only people who would be spared flooding to their homes are people who live along Couteau Ridge as well as any other elevations above I'd estimate somewhere around 27' above MSL.
I'm interested in this could you post your calculations on how you came up with 27'. I'd also like to see all charts and any other scientific evidence you have associated with this.
