> Does sediment build up and create new land near what used to be the mouth?
Yes, exactly right. This is what the entire southern coast of Louisiana is.
Envision the river like a wiggling hose spewing out water and sediment. As the sediment piles up in one area, that eventually is no longer the easiest path to the Gulf, and the hose jigs off to one side, finding a better path. When it does, it leaves behind huge, flat, fertile floodplains, bayous, and marshes. Then the new course too eventually fills up and it picks a new course again, often one of the previous ones which is now relatively more appealing.
It's been doing that for thousands of years, wandering around the southern coast of Louisiana, piling up sediment that flowed south into the great bayous and swamps.
That was until the Mississippi River became a giant trade path and New Orleans its terminus. If the Mississippi were allowed to change course and allow most of its water to reach the Gulf by going through the Atchafalaya River, the ports of Baton Rouge and New Orleans would be left dry. Meanwhile, Morgan City would be washed into the Gulf.
To prevent that, the Army Corps of Engineers has, for decades built barriers along the sides of the Mississippi to force the water to stay in that channel. Those barriers in turn reduce friction and cause the River to flow faster and faster. That means that instead of building up sediment at the current end of the river, that stuff is getting washed farther out into the Gulf.
Meanwhile, the Atchafalaya Basin and other areas which would have gotten their "turn" and had their own deltas built up have been left to erode with little new sediment coming into them.
This has been a well-known problem for longer than most of us have been alive. In the early 90s, I did a science project as a kid on it. But New Orleans has never been known for its long term planning. ("Laissez les bon temps rouler.") See also: Hurricane Katrina, which was an infrastructure failure more than a weather disaster.
So here we are.
Prediction: The only intended goal of this measure is to suck more federal cash into Louisiana which will be used to line political pockets. No real substantive ecological or infrastructure changes will come of it.
Yes, exactly right. This is what the entire southern coast of Louisiana is.
Envision the river like a wiggling hose spewing out water and sediment. As the sediment piles up in one area, that eventually is no longer the easiest path to the Gulf, and the hose jigs off to one side, finding a better path. When it does, it leaves behind huge, flat, fertile floodplains, bayous, and marshes. Then the new course too eventually fills up and it picks a new course again, often one of the previous ones which is now relatively more appealing.
It's been doing that for thousands of years, wandering around the southern coast of Louisiana, piling up sediment that flowed south into the great bayous and swamps.
That was until the Mississippi River became a giant trade path and New Orleans its terminus. If the Mississippi were allowed to change course and allow most of its water to reach the Gulf by going through the Atchafalaya River, the ports of Baton Rouge and New Orleans would be left dry. Meanwhile, Morgan City would be washed into the Gulf.
To prevent that, the Army Corps of Engineers has, for decades built barriers along the sides of the Mississippi to force the water to stay in that channel. Those barriers in turn reduce friction and cause the River to flow faster and faster. That means that instead of building up sediment at the current end of the river, that stuff is getting washed farther out into the Gulf.
Meanwhile, the Atchafalaya Basin and other areas which would have gotten their "turn" and had their own deltas built up have been left to erode with little new sediment coming into them.
This has been a well-known problem for longer than most of us have been alive. In the early 90s, I did a science project as a kid on it. But New Orleans has never been known for its long term planning. ("Laissez les bon temps rouler.") See also: Hurricane Katrina, which was an infrastructure failure more than a weather disaster.
So here we are.
Prediction: The only intended goal of this measure is to suck more federal cash into Louisiana which will be used to line political pockets. No real substantive ecological or infrastructure changes will come of it.