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The Morganza Spillway and the Atchafalaya Basin
The road between Lafayette and Baton Rouge crosses a large area called the Atchafalaya Basin. Years ago when the Mississippi River would flood it would spill over into the Atchafalaya and make a general mess out of everything. Early in the last century it became apparent the Mighty Mississippi was in danger of changing its course and overtaking the Atchafalaya Basin. The great flood of 1927 just about accomplished that. The river was 75 miles wide in some areas. That was when the COE began its work to contain the Mississippi. Among all the other levee and spillway systems built after that was the Morganza Spillway. The Morganza Floodway is designed to relieve the Mississippi flooding, but it wrecks everything downstream through the Atchafalaya Basin. The Morganza Spillway has only been opened twice since its completion in the ’50s: once in 1973 and once in 2011.
I spent time down there surveying in the middle ’70s. Most of what we worked on was repairing the damage from the ’73 opening. This Okie had never seen a real ‘river’ before then. We have a floodway constructed through central OK that is capable of a flow of 45,000 cfs. This pales to the 1.5 million cfs that will flow through the Morganza Spillway if all the gates are opened. The spillway was scoured (and repaired) after the 1973 event when only 30% of the gates were opened.
It looks like as early as June 2, 2019 the COE will open the Morganza Spillway. While the controlled release rates are still up in the air, but it is looking like it’s going to be a record event.
I fell in love with the folks (and the food and the music…and the beer) along the Atchafalaya while working down there. Just plain folks working to make ends meet, they would give you the shirts off their backs if you asked. Most of us don’t realize all the flooding that has recently taken place from Illinois to Nebraska to Arkansas all winds up down there in one place, the Mississippi. And it looks like this summer will be a bad one for folks down there. Imagine if you weren’t able to work all summer into September.
I bet they do what they can make it through hard times and high water. But I’m saying a prayer for them anyway. The river does what it wants and no man will ever stop it. Bonne chance mon amis. Dit une pri??re.
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12 Replies
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Mr. Cash ?? some good observations.
John McPhee ?? a writer one should become familiar with ?? wrote an essay on this situation, summarized here:
http://yang.sdsu.edu/special_lecture_02_mcphee_atchafalaya.html
I hope the river does not win, for the sake of the downstream residents, but it will, someday.
Ken
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The most excellent article by John McPhee on the complexities of the lower Mississippi can be found and read at
https://www.newyorker.com/magazine/1987/02/23/atchafalaya
GB
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The river keeps a talking…
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Today I just read the Corp will definitely open approx. 10% of the gates at the Morganza Spillway around June 2. In the article it also mentioned plans to sink a barge near Morgan City to help minimize flooding.
I’m not an engineer…and to me, hydraulics are akin to witchcraft…but sinking a huge barge to help with flooding seems sort of like placing burning cars in strategic locations to help with traffic congestion on the Interstate….
But I apparently don’t know more than I though I didn’t know.
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Water is going downhill all the way to the Gulf and nothing is gonna stop it, it is just gonna find another way around or over any dam or embankment that is built.
Everything built to deter the flow will simply make the main waterway smaller and it will spread out and flood something.
One of the largest problems with south Louisiana is that the inhabited land is below sea level.
Anyone remember the name of that song Leroux sang about everything from upstream was going to wash them away someday?
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..One of the largest problems with south Louisiana is that the inhabited land is below sea level.
The author John McPhee (mentioned above) noted the Mississippi River contained in levees resembled more a “bulging vein on the back of your hand” than a river.
I can understand how all the levee and controls evolved over the twentieth century. But even those folks that tend to the River will admit it’s only a matter of time until it finds a quicker and shorter route to the Gulf.
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73 the Morganza was almost lost because of current (whirlpools) acting to undermine the structure. River would have changed course.This was all described by McPhee. A group of COE surveyors literally risked their lives by taking leadline soundings during the event.
Another thing to worry about, if one needs to worry about something is the strength of the River levees upstream from Baton Rouge to Natchez.
The right descending bank historically has some weak points with score of sections that boil. Same is true within the Basin itself along the west perimeter levee that have slides. If your going to live full time in the Basin, you better live on a houseboat or barge converted to one. But there are a few small communities along the Atchafalaya within the Basin that will flood.
But flooding isn’t the main concern, the River changing course would end life as we know it in the USA. That’s why they have been plans that have dragged along for an offshore port in the Gulf for many years.
Plugging a bayou with a barge is equivalent to placing a huge sandbag, it is meant to impound and ease flow.
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When they opened the Atchafalaya in 2011 I received a call on a Sunday from a local surveyor wanting two digital levels ASAP. They weren’t sure what would happen when they opened it since it had been 38 years and was only the second time, they wanted to monitor it.
As I understand it, the barge is supposed to prevent the water from backing up and flooding west Terrebonne Parish, which has already experienced flooding just from everything being as high as it is. We shot top of water on the Atchafalaya River about ten days ago at 15.8′.
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The barge is for back water flooding in several low lying communities North of Morgan City. It has worked before. We are part of the survey and design team for a
permanent solution.
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http://www.radicalcartography.net/index.html?fisk
The characteristic action of the Arkansas River in taking away from one and giving to another was strikingly described by the talented Arkansas writer, S. D. Dickinson in an article on the River published in the June 9, 1946 issue of the Arkansas Gazette, as follows:
“Whimsical, persistent, violent, quiet, the Arkansas swerved back and forth across the alluvial fan. From the rocky bluffs in the Little Rock area it twisted like a snake held by the tail. It could not rest in its own bed. It was a masculine dance the river performed ?? a tandava such as the ancient Hindu god Siva danced, revealing perpetual creation and perpetual destruction?? It gave as lavishly as it took away.”
In this connection, we might point out that Judge Woodrough, in Chicago Mill & Lumber Company v. Anderson-Tulley, 8 Cir., 130 F.2d 268, 269, characterized the Mississippi River as writhing “like an imprisoned snake throughout its alluvial valley in its futile effort to establish equilibrium”.
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Thanks for the input from someone who has knowledge about the issue. Oh, and it’s good to hear from you again.
Andy
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