I remember reading Twain’s essays about the Mississippi, and was especially enamoured of how the river was shortening itself constantly. Looking over close-up maps of the state of Mississippi and Louisiana recently certainly demonstrated just how much the river has changed its course since those state borders were drawn. Lots of oxbow lakes and bits of each state that are now completely separated from the rest of the state by the river.
It clearly shows that the river is moving towards being a much straighter line between Cairo and the Gulf of Mexico.
Now I understand that control structures are in place to keep the mighty Mississippi river mainly in its own bed, and keep it from jumping completely down into the Atchafalaya river bed to make a new delta south of Morgan City.
But I’d like to know if the big Muddy is being kept from continuing to shorten inself by cutting out other loops, and if so, where and how.
Anybody got good info on the current state of river engineering there?
False starting point: unrestrained rivers like the Miss. meander over time. Some of this shorten the local length, and some add to the length. This is most common with rivers that run thru flattish country and carry a lot of silt. The silt raises the level of the riverbed until the point when during a flood, the river finds a lower place to cut thru nearby. Length is not so important compared to elevation.
Of course, thanks the the Army CoE, meandering is Not Acceptable. But, Mother Nature ignores Army orders in the long run.
Then may I assume the fact that the Mississippi has become much straighter in the last 150 years is due to man’s intervention?
And are there any particular points in any rivers around the globe where mankind is trying hard to keep the river from changing course? I imagine a lot of port cities don’t want to find themselves suddenly landlocked.
Although perhaps if we just let the Mississippi have its way and course into the Atchafalaya riverbed, we wouldn’t need to rebuild NOLA, since it wouldn’t be a viable port anymore?
The Los Angeles River is paved for almost its entire length because it was seasonal and would cut a different channel each year. This wasn’t fun for most people who lived near it. So it’s paved most of the way.
People have been quite busy very many centuries “fixing” rivers. One of the most notorious examples outside of the US is the Yellow River in China. Here’s a summary about it, including comments on course changes and levee breaches. Some of the videos I have seen of the river is quite startling: boats floating on the raised river well above the surrounding farmland.
And yes, some straightening of the Mississippi has been done in order to improve navigation and to some extent to make levee building easier.
During the Flood of 1993, the Missisissippi and Missouri jumped banks to join at a point several miles to the west of their normal confluence. Rivers being what they are, they continue to try to turn that shortcut into a permanent channel.