re: Someone Educate Me About Diversions

I listened to a talk Kerry St. Pe did on costal.erosion. He said there is 80% less sediment in the water column today as there sas in the early1900s. Mostly due to the 80 water control structures on the MS River.

Exactly. I wish I could go back in time and go through the swamp before it was all compromised.

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fishermen need to realize that they have 1 of 2 choices to make.

take a hit now with the diversions and adapt to new fishing areas

or fight the diversion and watch as in 30-40 years, there is no where left to fish period.

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While this isn't necessarily false, I think it's important to understand the commercial fisherman (and recreational) side of the argument. For commercial fishermen, this literally is their livelihood. My best friend makes 3/4 of his money for the year trawling and oyster fishing from the Rigolets to Shell Beach to Cocodrie and so on. His entire family is from Shell Beach and they all do the same. So for them, it literally is their livelihood and it's pretty understandable why they're so quick to "diversions = no life."

On the other hand, something does need to be done. The question becomes how to find a balance between taking proactive measures while avoiding the destruction of these peoples' livelihoods.

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bluemoons

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true

This too. It would be epic to see the swamps before all the cypress trees were cut.

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fishermen need to realize that they have 1 of 2 choices to make.

take a hit now with the diversions and adapt to new fishing areas

or fight the diversion and watch as in 30-40 years, there is no where left to fish period.




While this isn't necessarily false, I think it's important to understand the commercial fisherman (and recreational) side of the argument. For commercial fishermen, this literally is their livelihood. My best friend makes 3/4 of his money for the year trawling and oyster fishing from the Rigolets to Shell Beach to Cocodrie and so on. His entire family is from Shell Beach and they all do the same. So for them, it literally is their livelihood and it's pretty understandable why they're so quick to "diversions = no life."

On the other hand, something does need to be done. The question becomes how to find a balance between taking proactive measures while avoiding the destruction of these peoples' livelihoods.

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I think that it is importatnt for the fishermen (of crabs, shrimp, saltwater finfish) to understand that it was prior human modification to the Mississippi River System, namely for flood controll, that has created the existing unsustanible fishery. But 3 generations hae gone by and i find that is usually sufficent for the existing condition to be extraploted back into the past and the argument of "well, this is how it always was" gets kicked out. I think this was mentioned earlier in the thread....

No, that is not the case. deltas are very complex and deposition in most major river basins tends to be cyclical.

Successful land building sediment diversions would restore a once active and vital PROCESS in the current delta, as opposed to say the instant gratification of marsh creation which is the restoration of a pre-existing landscape to as close as possible to some pre-existing configuration.

Process restoration is for the long haul, for you great grand kids and beyond.

People need to look past their noses sometimes...

Where are our resident experts?

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listened to a talk Kerry St. Pe did on costal.erosion. He said there is 80% less sediment in the water column today as there sas in the early1900s. Mostly due to the 80 water control structures on the MS River.

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There is far less sediment making it down the river then in the early 1900's but I think the number is closer to 40-50% rather than 80%. And it it not due to structures on the Miss River.

The Miss River gets most of its sediment from the Missouri River while most of the water volume comes from the Ohio River. Dams and/or reservoirs built on the Missouri is what is causing the decreased sediment loads.

Look at the wax lake outlet as a model for diversions working.


The Mississippi River is a typical bird foot delta. However because of dredging the channel and leveeing the banks, the velocity of discharge is increased causing the deposition of sediment to move further offshore instead of where it would normally be, which is in the marsh surrounding its distributaries, and mouths. The levees stop the annual floods which deposit sediment in crevasse splays and in the upper delta.
The diversions are an attempt to supply fresh water and sediment to areas deprived of this by the levees and channelization. Some work and some don't.

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Look at the wax lake outlet as a model for diversions working.

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Wax Lake is always open. You can't shut it off. It flows from as little as 20,000cfs to 300,000cfs during floods. Yes it is working, it is building land. Land that is not washed away when a hurricane comes. It also has a thriving freshwater marsh. Notice I said freshwater marsh. No one is catching trout or harvesting oysters near its mouth.

And that is the problem. In order to get a diversion that builds land and have a thriving marsh that can withstand hurricanes you can't turn it on and off. You need to let the natural process of high water floods (Jan. to June) happen. this water is all fresh and full of sediment. Then when the water levels fall the salt water can naturally encroach the area. Salt water does not necessarily mean death to fresh water marsh. When fresh water marsh is inundated with salt water the marsh roots actually grow deeper to find fresher water. Thus making them stronger.