Is This The Year The Atchafalaya River ‘Captures’ The Mississippi?

Forbes.com ^ | 5-16-11 | Forbes

[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 today–it would have forced a new path down the Atchafalaya basin, a course that is some 20 feet lower than the river’s 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 river’s 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.

[Aliska]

Not intended as criticism by any means, but something causes the river to meander, doesn't just happen.

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.

[cripplecreek]

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,

Interestingly enough, the controlled Nile is one source of their problems in Egypt. No more seasonal flooding and the farmers deplete the soil making the country more reliant on the outside world for food.

[Defiant]

By the way, do you know the difference between a Texan and a jackass? The Sabine River.

[dynachrome]

“periodic flooding like this is what replenishes farmland with valuable solids”

The Nile delta used to grow a lot more food back when.

[.45 Long Colt]

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.

[Elderberry]

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.

[Nepeta]

Water always wins.

[killermosquito]

Why don’t we put a dam on the Mississippi?

[thecodont]

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.

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.

[Bean Counter]

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.

[Always A Marine]

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.

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.

[centurion316]

Not intended as criticism by any means, but something causes the river to meander, doesn't just happen.

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.