I just finished an incredible New Yorker article by John McPhee (open link here) written in 1987 (the year I graduated high school!) on the and compelling saga of the Mississippi River. He tells a captivating tale of the conquest of the Mississippi by the adjacent Atchafalaya River and the 200+ year-old battle by the Army Corp of Engineers to keep this event from coming to pass.
A river, wanting nothing so much as to reach the sea by the shortest and steepest route, will always find the offer of such a path an irresistible lure, and in this case the Atchafalaya offers a path half as short and twice as steep. But since Europeans began settling Louisiana in earnest, such an event has been found completely unacceptable (and was duly noted by perceptive observers ever since there were significant European settlements to speak of). The mandate to fight this war with nature fell on the Army Corps mostly by virtue of being the nation’s first preeminent body of engineering to whom the job could be delegated, a questionable gift that was bestowed by Congress in 1879.
The battle has been pressed in earnest since then with what must be admitted as relatively impressive results, yet the flooding of this past May and June from Illinois all the way to Louisiana is a fresh reminder of the utterly implacable nature of rivers and water, which have all the time in the world to just keep flowing. Particularly in this age of climate-change induced severe weather events, the coming century is likely to make the major events of the last several decades look like the new normal. And nothing less than the immediate destruction of a city of more than 12,000, much of major industry, agriculture and fisheries, even the very literal, physical shape and landmass of Louisiana hang in the balance.
The fulcrum of this saga is the Louisiana Old River Control complex and in particular the Old River Low Sill Control Structure (and auxiliary control structure). Seen from a human scale, this is truly an impressive structure, monumental in scale from the view offered from off the side of US 15, which crosses it.
However, move to merely a bird’s eye view and the sisyphean nature of the Army Corp’s task begins to materialize:
Fly up to an even more godlike view and the task begins to look a lot like the display of hubris that many critics have likened it to since the decades ago that the project began.
(photo: Google Earth/USDA FSA)
The Old River Control Complex, which is all that stands in the way of a permanent rerouting of the river, is composed of the small strips of roadway on the right-ish angle sides of the isosceles triangle of land on the right-hand side of this image.
The original single Low Sill Structure (uppermost of the now 2 structures in this current picture) meters water flow into the Atchafalaya River in a 30%/70% relation with the Mississippi, a rate frozen in time since 1953, when the structure was conceived. In 1973, a mere 10 years after its completion a flood well under the proportions it was designed to handle nearly took it down, which would have almost certainly resulted in the irreversible capture of the Mississippi by the hungry Atchafalaya, a process aided by a number of early engineers and river pilots who cut through natural barriers between these 2 rivers in the name of speedier navigation and commerce. Here is a picture of the structure which clearly shows the collapse of one of the wing walls due to scouring (red circle) by the river’s turbulent waters at flood stage. (photo: americaswetlandresources.com)
I could go on, but you should just read the excellent article in its entirety. McPhee uses a number of somewhat fluvial landscape-specific terms throughout, but given that one would be reading it on the internet, a quick search will get a non-scientific reader right back on track (I happened to have just completed a science class which spent some time on some of this material, but there are plenty of easy resources and I got really link/search crazy while reading this story anyway).
Anyway, read it!
Some resources I was cruising as I read:
Here’s a good map showing some of the recent inundation scenarios from the May/June floods.
Then there’s Google Earth. Zoom in…