Mississippi River and coastal erosion question... | TigerDroppings.com

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loogaroo
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between Hayes and Bell City
Member since Dec 2005
1353 posts

Mississippi River and coastal erosion question...


Why not dredge a channel through Lake Pontchartrain to the Bonnet Carré Spillway?

Then, build a big enough set of locks (at the current spillway) to keep two way traffic going on the river, which also could serve as a spillway.








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bayoubengal03
LSU Fan
Member since Nov 2006
937 posts

re: Mississippi River and coastal erosion question...


You lost me.... Will this slow erosion?





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CITWTT
LSU Fan
baton rouge
Member since Sep 2005
31765 posts

re: Mississippi River and coastal erosion question...


Why build this new fangled spillway? The water volume that goes south of the Bonnet Carre is necessary to be at that level for shipping purposes and also potable water for a very large population. If you desire to make changes to deal with coastal erosion there are better methods to use.





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4LSU2
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Madisonville
Member since Dec 2009
21601 posts

re: Mississippi River and coastal erosion question...


How does this replenish the marsh to the west of New Orleans?





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Placebeaux
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One man's LOL is another man's WTF
Member since Jun 2008
23680 posts

re: Mississippi River and coastal erosion question...


When it comes to fighting erosion, I always was a proponent of creating flood plains south of New Orleans where the river could flow into the marshes during the flood season.





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GumboPot
LSU Fan
Saints Fan
Member since Mar 2009
23921 posts

re: Mississippi River and coastal erosion question...


quote:

When it comes to fighting erosion, I always was a proponent of creating flood plains south of New Orleans where the river could flow into the marshes during the flood season.


Well we do have a few diversion projects that do just what you are describing (to offset the damage the levees have done to the marsh).






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CITWTT
LSU Fan
baton rouge
Member since Sep 2005
31765 posts

re: Mississippi River and coastal erosion question...


A more complex, but I think greatly better way of accomplishing the rebuilding of the marshes is this. Build pumping stations along the levees south of Belle Chase on both sides of the river and offload the material picked up by the dredges which is used to keep the river navigable for shipping, presently that material is dumped at the mouth of the river into the gulf. Both the need to keep the river open for one reason and the need for "silt" are accomplished at the same time.





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GumboPot
LSU Fan
Saints Fan
Member since Mar 2009
23921 posts

re: Mississippi River and coastal erosion question...


quote:

Why not dredge a channel through Lake Pontchartrain to the Bonnet Carré Spillway?


Channelization is detrimental to marsh growth.



This post was edited on 8/30 at 6:57 am


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GumboPot
LSU Fan
Saints Fan
Member since Mar 2009
23921 posts

re: Mississippi River and coastal erosion question...


Good idea.





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Quidam65
Florida Atlantic Fan
Q Continuum
Member since Jun 2010
8619 posts

re: Mississippi River and coastal erosion question...


quote:

How does this replenish the marsh to the west of New Orleans?


It wouldn't. The only real way to do that is to let the Mississippi flow through the Atchafalaya which it wants to do anyway.






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Taxing Authority
LSU Fan
Houston
Member since Feb 2010
22097 posts

re: Mississippi River and coastal erosion question...


quote:

Channelization is detrimental to marsh growth.
This. You have to slow the water down so the sediments drop out.






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Zephyrius
LSU Fan
Covington, La.
Member since Dec 2004
2913 posts

re: Mississippi River and coastal erosion question...


A little bit of a twist...

In the early 1800s there was a plan to make Bayou St. John the port of New Orleans because access from the Gulf into the Lake would have been a shorter and direct line into the city.

Hind sight being 20/20... if this came into to fruition you wouldn't have needed such a monumental and encompassing levee system but maybe minor one to protect the City and the smaller communities to the south.

Then you could have built a more elaborate spillway/ dike system at Morganza where you could control flood levels flowing water either through the actual Mississippi River and through the Atchafalaya.

The encompassing levees along the entire river to Venice would not have been needed and would have allowed sentiment to move through the natural flood plains.

Even with this system there would have been erosion but probably extended the life of our present marshes(Venice to Timbalier Isles) another 100yrs or so...

ETA: The man who had the idea... James Pitot Wikipedia Link
quote:

He was President of the New Orleans Navigation Company, which was granted the right to operate a toll canal extending from Bayou St. John into the Tremé neighborhood,terminating in the 'turning basin' which eventually gave its name to Basin Street. This route saved shippers many expensive days and risks of navigating the winding Mississippi River, in the days of sail.[1]






This post was edited on 8/30 at 8:41 am


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diplip
LSU Fan
Half-way to Valhalla
Member since Jan 2011
276 posts

re: Mississippi River and coastal erosion question...


quote:

A more complex, but I think greatly better way of accomplishing the rebuilding of the marshes is this. Build pumping stations along the levees south of Belle Chase on both sides of the river and offload the material picked up by the dredges which is used to keep the river navigable for shipping, presently that material is dumped at the mouth of the river into the gulf. Both the need to keep the river open for one reason and the need for "silt" are accomplished at the same time.


Sounds good in concept...however, 90+% of the dredgeing is done below Venice. The cutterheads are not mobile, and it would cost way too much to have the hoppers make a 120 mile round trip with a pumpout in middle... It aint gonna happen like that. Ever.

Now, if they start doing something with the material dredged from the crossings between BR and NOLA, you could have a viable idea. right now they just dredge the crosssing with a dustpan or cutterhead and dump it right back in the river, and then dredge it again at the next crossing down... Concieveibly it could be loaded on barges and pumped out at Belle Chasse






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LSUgusto
Member since May 2005
16247 posts

re: Mississippi River and coastal erosion question...


The major leveeing of the river was in response to the flood of '27, though, and not really about keeping the river deep for a New Orleans port. No?





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Zephyrius
LSU Fan
Covington, La.
Member since Dec 2004
2913 posts

re: Mississippi River and coastal erosion question...


I would think its more to keep the ports/ infrastructure from flooding which would halt commerce.





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CITWTT
LSU Fan
baton rouge
Member since Sep 2005
31765 posts

re: Mississippi River and coastal erosion question...


The Atchafalaya would not reach much farther to the east of it present course so it won't help with the west bank marshes at all. This is why the pumping of the silt from below the beds of the Missisippi out towards the marshes directly with wngineered and controlled flow makes the best use of the money. The money itself was voted upon in the last two or so years by Congress, now it is only using that stuff to the best effect. From the west bank levees it can start at or near the south of Belle Chase to the coast and about the same starting point on the east bank. the manufacturing of islets from which an expanded network of pumping stations in the Barataria region would be a damned good start





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GREENHEAD22
LSU Fan
LafayettebywayofBush
Member since Nov 2009
8002 posts
 Online 

re: Mississippi River and coastal erosion question...


Start poking holes in the levee, only way shite will ever be helped.





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LSUgusto
Member since May 2005
16247 posts

re: Mississippi River and coastal erosion question...


I can't wait to see what happens down Bayou Lafourche once Mississippi River water begins flowing down it again. I'm curious, will the fertilizers responsible for the dead zone in the Gulf have a beneficial impact on the estuary?





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geauxtigers87
USA Fan
NOLA
Member since Mar 2011
6672 posts
 Online 

re: Mississippi River and coastal erosion question...


only thing that will fix it is blowing up the levees in plaquemines parish and letting the river do it. no one has the political will to do it though





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