Growing Concern about Mississippi River Course Change
Growing concern about Mississippi River course change.
The Mississippi River has changed course to the Gulf every thousand years or so for about the last 10,000 years. Gravity finds a shorter, steeper path to the Gulf when sediments deposited by the river make the old path higher and flatter. It’s ready to change course again. It wants to take a short cut at the Old River Control Complex down the Atchafalaya River to the Gulf at Morgan City, Louisiana. It’s 193 miles shorter and steeper and faster than going by New Orleans.
Gravity makes water flow downhill. The higher the hill, the greater the “head” or force driving the flow. Floods on the Mississippi raise the water level inside the levees and increase this force. Floods are becoming more frequent, longer, and higher — even though average annual rainfall in the Mississippi drainage basin has been almost flat since 1940.
It has flooded every other year on average since 1972 vs. once every six and a half years 1940-72. It has flooded eight of the last ten years at Natchez. There have been two hundred-year floods within five years (2011 and 2016). The odds are over a thousand-to-one against this. The average level or stage of the river has risen ten feet at Natchez since 1972.
So, the head or force to drive a course change is increasing. Hence, the odds of a course change are too. Ironically, this is due in large part to work by the US Army Corps of Engineers, which is supposed to control floods. And by the Corps operation of the Old River Control Complex (just above Baton Rouge), where it restricts the Mississippi’s flow into the Atchafalaya to 23% of its volume. This restriction, together with work by the Corps to shorten and straighten the river and speed its flow, has caused it to rise. And to flood more.
These floods now damage property inside the levees and along the Mississippi’s tributaries (about 1.5 million acres from Greenville to Baton Rouge). But they could lead to a catastrophic levee failure — and course change. And to much greater damage for Louisiana and the nation.
That’s the subject of a recent article in The Advocate of Baton Rouge and also a similar recent article in The Times Picayune of New Orleans. It’s also something we have been talking about and testifying about before the Mississippi River Commission for the last two years.
when did the authorities/scientists realize the river was changing course?
An excellent book on this subject is John McPhee’s The Control of Nature.
You might google ” Old River Control Complex ”
The short answer, I’m afraid, is “as long as engineers have been studying it.”
The water crisis in the desert SW can be averted IF the flow INTO the Mississippi is substantially reduced by doing a diversion of the Missouri River’s excess flow just South of the Platte River concurrence and pipe water to the San Juan River in SE Colorado which flows to Lake Powell. This location would save billions in pipeline and pumping station cost construction since it’s at a higher elevation than the Mississippi River just South of St. Louis and hundreds of miles farther West. This diversion project would reduce the inflow into the Mississippi River enough to offset the higher incidence of flooding downstream along the Mississippi border with Arkansas/Louisiana and into the state of Louisiana itself. From an economic perspective it’s a win, win all the way around.
Thank you for a sharing insight and future possibilities.
I’m from Simmesport, La., Which is on the Atchafalya River not far from the Old River Control Structure. I’ve seen that 23% of the Mississippi River come through the gates into the Atchafalya. 23% doesn’t sound like a lot but believe me it is. The amount of water and the force of said water coming through those gates is jaw dropping and very scary. I’ve seen it multiple times. Every year more and more water comes through the gates so it’s concievable that one day too much is gonna come through and take that structure down. It’s only a matter of time.
This has been a ongoing problem since I was a child studying Louisiana history in the 8th grade in Winnsboro in 1959 or 60. It is just getting more dire. It will not only destroy Louisiana it will effect the whole if USA.
Water only flows uphill in bond elections and political speeches. The Mississippi will change course when the subterranean river delta meanders to the point that the surface flow cannot be contained by simple earthen agricultural dikes or “levees”.. We are presently “overdue” for event.
How foolish are we humans? For millions of years the path of this river has meandered as it pleased. Dictated by geology and gravity. For us to try and control it and cry disaster when it doesn’t bend to our demands is peak hubris. Just like building large cities in deserts and saying there’s no water! Silly humans are we…