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Author Topic: Louisiana land loss  (Read 3842 times)

paul.fr

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Louisiana land loss
« on: 14/12/2007 15:07:51 »
Louisiana loses about 30 square miles of land each year, so i hear. So where does it go?


 

another_someone

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Louisiana land loss
« Reply #1 on: 14/12/2007 18:03:06 »
Deep out to sea.

The problem did not used to happen, because the Mississippi used to dump lots of silt as it flowed into the Gulf of Mexico, but as a by-product of improvements in the navigability of the river, they reduced the amount of silt it dumped in the estuary area, so now that silt is being taken further out to sea, and being dumped in deep water.
 

Offline JimBob

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Louisiana land loss
« Reply #2 on: 16/12/2007 19:09:39 »
Actually, it is moving to Texas, literally. The Louisiana delta is not really being eroded but is subsiding. Any movement of sediment is to the west at present by dominantly long - shore currents. These long shore currents, moving from east to west, form the Channier ridges in Cameron Parish and the swamps of the Atchafalaya Basin. The sand is carried all the way to the south of Corpus Christi, Texas.

The reason the Mississippi delta region is loosing ground is because of the US Army Corps of Engineers. At the end of 1963 they finished the Old River control Structure and dam which allows water from the Mississippi to flow into the Atchafalaya basin at a controlled rate. Otherwise, the Mississippi would have already changed course and there would be little or no navigation on the Mississippi at all south of Simmsport, Mississippi, where the control structure is located.

The consequences of no navigation on the lower Mississippi would be disastrous as sea-going vessels go as far up river as Baton Rouge, Louisiana to unload cargo - about 200 miles. Land loss in Louisiana is due to subsidence, not the dirt being washed out to sea.

All of this will eventually be to no avail as the Mississippi will change course and the Corps will losses their constant battle to stem the amount of water moving into the Atchafalaya River Basin.

 

The Naked Scientists Forum

Louisiana land loss
« Reply #2 on: 16/12/2007 19:09:39 »

 

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