Skip to comments.Is This The Year The Atchafalaya River ‘Captures’ The Mississippi?
Posted on 05/18/2011 5:36:41 PM PDT by dynachrome
Could it happen this year? The U.S. Army Corps of Engineers is forcing the river down a path it no longer wants to travel. Had the river gotten the best of the engineers in 1973 the Mississippi would not be the same river todayit would have forced a new path down the Atchafalaya basin, a course that is some 20 feet lower than the rivers current main stem, and which offers a 150-mile shorter path to the Gulf of Mexico. Its course has changed dozens of times over the millenia, sweeping back and forth like a garden hose, and will change again. You can see a beautiful map of the rivers countless meanders here, and download a full set of historical maps here.
McPhee spent months trying to understand the centuries of engineering prowess that have gone into trying to control the Mississippi, especially the creation of structures much in the news today, like Old River Control and the Morganza Floodway, which was opened over the weekend to allow floodwaters to course down through the Atchafalaya basin.
(Excerpt) Read more at blogs.forbes.com ...
A very interesting article at the source.
Maybe it will be like the old days with guys cutting new channels to leave their neighbors high and dry!
Gives me a “not available” page?
Never mind. got the 2nd post.
The link didn’t work to get me to the graph. You’ll have to make your own plot.
If they do that will Morgan City and Houma flood?
Yeah except the Discovery channel will make it into a “reality” show. :)
Sure looks like it. I get the impression the C of E isn’t going to have a choice on this one. Paging Kanye West......
It seems that river wants to meander. When man tries to change what God has created and then builds cities relying on “man’s power” to control things, man will lose every time. If God wants the Atchafalaya channel to take in the Mississippi and destroy Morgan City, so it will be. We can only watch in wonder at his power and praise him for his creation.
McPhee should be required reading for anyone living in the Mississippi/Missouri/Ohio River Basins. Add to that John Barry’s book, Rising Tide that tells the story of the 1927 flood. You must understand the river if you intend to live within its reach, and these two writers provide an insight that everyone can understand.
Among the lessons that come clearly to light are that man can do much to control this mighty river, but in the end, the river will prevail. The Atchafalaya will capture the Mississippi, of that we can be certain. Without the extraordinary engineering efforts that have been undertaken in the past 130 years, it would have happened already. But, someday, the river will win and the Old River Control System and the Morganza Floodway will be undermined during some massive flood event and the river will carve a new channel to the Atchafalaya basin and it will be game over. I don’t think that it will happen this year, at least based on reports of the last few days. The system has worked as designed and we don’t have any apparent undermined/scouring that might destroy the flood control structures. We have dodged a bullet. But, the river is patient and she will win some day.
I still remember the first time I drove on Hwy. 90 from Florida to Texas in 1970. For maybe 25 miles there was nothing but swamp and rivers. One bridge after another until I finally came to the Huey Long Bridge.
The Atchafalaya must be the biggest swamp in the world.
When I was a kid in high school, they taught us that periodic flooding like this is what replenishes farmland with valuable solids from the river sediment. Periodic flooding is not necessarily a bad thing, and it sounds like many of the residents already know that, and many had long-standing plans on how to evacuate now, and pick up the pieces later.
I saw one guy on the news last night who stripped his home of everything, including the kitchen cabinets, the hot water tank and the air conditioning condenser unit. He’s prepared to make whatever repairs to the sheetrock he has to, and then reinstall everything again.
Look at the circuitous path the river takes starting roughly at Prairie du Chien, WI and due southward to Burlington, IA. Something has prevented the river from taking a more due south course which I suspect are the high bluffs in the area, could be wrong.
It does meander for sure, further south but still considerably upstream from LA, it really meanders in tight switchbacks.
As to God, I don't disagree; however He set into motion the laws of nature that cause rivers and bodies of water to behave as they do. Great thread.
By the way, do you know the difference between a Texan and a jackass? The Sabine River.
“periodic flooding like this is what replenishes farmland with valuable solids”
The Nile delta used to grow a lot more food back when.
Excellent suggestions. I would also recommend Pete Daniel’s Deep’n As It Come: The 1927 Mississippi Flood. Rising Tide really tells the story and is the better book, but I suggest Daniel’s book for the photos.
Another worthy narrative is the classic memoir Lanterns on the Levee, by William Alexander Percy. The book covers much more than the flood, but Percy had a unique perspective because he headed the relief effort at the behest of his old friend, Herbert Hoover.
Anyone who loves literature should read Faulkner’s “Old Man” from If I Forget Thee Jerusalem.
Back in the late 70’s I had an elderly neighbor that grew up on the Mississippi. He talked of people on the river being against the levys. And how many times they were dynamited. And how the farmers were dependent on the annual flooding of their farmland. He also said that they built their buildings up on cork oak logs so that they would float during the floods.
Water always wins.
Why don’t we put a dam on the Mississippi?
Add to that list Lanterns on the Levee: Recollections of a Planter's Son by William Alexander Percy, for another perspective on the great flood of 1927.
Then this flooding ought to prove to be a real boon to the farmers down there once the damage is fixed and the mess cleaned up. Those farmers will be rewarded for years with production increases.
I’m glad it’s not all bad news. I’ve already heard more than one brainless talking head refer to this as the equivalent to a tsunami, and nothing could be further from the truth.
Rising Tide is a great recommendation. A friend gave it to me two years ago as therapy for my workaholism, and I have since passed it along to two friends who grew up along the Mississippi River. Barry's account of the long political duel between engineers Eads and Humphreys over methods to control river was fascinating, as was his account of how the flood's devastation led to the rise of the despotic Huey Long. I hate to think about how people would react to a similar catastrophe today.
Rising Tide is a monumental work and a great, great read.
The simple answer is, its all about sediment. A flowing river contains a certain sediment load, and maintains a flow rate in order to keep that sediment suspended. When it comes to a bend, the water on the inside of the bend flows slower than the water on the outside of the bend. This causes the river to deposit sediment on the inside and cut into the bank on the outside. That's how meanders move.
The reason that you get meanders in the first place is that the river will adjust its slope to most efficiently move the water and the sediment within its banks. When you get more water in times of flood, the river will scour its bottom downstream in order to increase the slope and move the water faster. It also wants to straighten its course, since any drop in elevation over a shorter distance will increase the slope. When the flood waters are gone, the river starts to deposit sediment on the river bed and tends to meander in order to return to a flatter slope.