Louisiana spillway opened to relieve Mississippi River, spare cities from flooding [protect Orleans]

Los Angeles Times ^ | 5-14-11 | By Tina Susman, Los Angeles Times

[NoLibZone]

The Army Corps of Engineers begins diverting water to a flood plain, a move that will slowly swamp farmland and small towns to relieve pressure on levees protecting New Orleans and Baton Rouge.

Reporting from New Orleans— In a last-ditch move to relieve stress on levees burdened by Mississippi River floodwaters, the Army Corps of Engineers on Saturday opened a spillway to gradually inundate a major floodplain for only the second time in nearly 40 years, funneling water over farmland and small communities to save New Orleans and Baton Rouge, La., from inundations.

At 3 p.m. CDT, a large crane lifted the metal teeth on one of the Morganza Spillway's 125 gates, marking the first time in the nation's history that three of the Mississippi River spillways were opened at the same time. The New Madrid floodway in Missouri and the Bonnet Carre spillway in Louisiana were opened earlier this month as the river reached record or near-record levels in several states.

[UB355]

I wonder how the Swamp People as depicted on the History Channel are affected ?

[dirtboy]

So, you have a choice, let the river overtop the levees wherever it wants with almost certain destruction of many cities and towns;

Not only that, but if a levee on the south side of the river were to fail, it could well end up cutting a new channel for the river - that is what the Old River structure and the Morgana spillway are meant to try and prevent. The distance to the Gulf via the Atchafalaya is half that of the main river channel. And that is a powerful difference - the river wants to go that way, and only man-made structures are preventing it.

[AGreatPer]

They built this stuff for an emergency flood. This is it.
Won't happen for another 25-50 years.

[muawiyah]

There's an attitude about the rivers that you have to see to believe. Indianapolis has a bunch who like to live along White River (a Wabash tributary) ~ and every year or so the river goes out of its banks and floods their neighborhoods.

They love to be hauled out of there on small boats.

Then, the river goes down and they go back home. They probably spend 2 weeks cleaning the muck out, but you'll see them down there all summer long fishing in their backyards, or a neighbors, drinking beer and barbequeing.

You can't get flood insurance for this ~ not even federal flood insurance ~ but you can't get the ambience and lifestyle of the riverfront unless you live there.

They almost all have a motorboat parked out front.

[abb]

See here what the system is designed to handle at the max.

As of today, the flow rate at Natchez, is 2,120,00 ft3/sec. The forecast maximum flow is for 2,340,000 ft3/sec., well short of the design limits of the system at 2,720,000 ft3/sec. See here the forecasts for Natchez, MS.

http://weather.hamweather.com/rivers/gauge/NTZM6.html

[LibFreeOrDie]

I wonder how the Swamp People as depicted on the History Channel are affected ?

Many will be affected. Cajun country:

[deport]

This image gives a perspective of the drainage from the US that is coming to a focal point as it enters the Gulf of Mexico thru the Atchalafaya and Mississippi Rivers in South Lousiana.

[meatloaf]

The Mississippi at Vicksburg is running at 2.2 million CFS. That’s about 15 million gallons per second.

http://rivers.anglerguide.com/flows/hw3.php?forecast=riversobs&gauge=VCKM6

[abb]

They built this stuff for an emergency flood. This is it. Won't happen for another 25-50 years.

Yes, but the system is also designed to prevent the Mississippi River from changing course. One day, there will be a thousand-year flood and all the systems won't be sufficient to handle it.

I remember well the 1973 flood and the opening of the Morganza that year. I fished for a week in the Lower Atchafalaya Basin that summer. Lots of fish caught. The Basin is one of the best fishing holes in the Southern United States.

[centurion316]

You’re exactly right. The Mississippi will be captured by the Atchafalaya, its just a question of time. The shorter distance means that the slope along the Atchafalaya is greater and the river wants a steeper slope to more efficiently carry all the water and sediment load. Keeping the river in its channel all these years has raised the bed of the river in its lower reaches and reduced the overall slope. The river doesn’t like it, and someday during a flood event, it will find a path to the Atchafalaya and that will become the new route to the Gulf. That’s how the Delta was built over many millennia.

[trumandogz]

“Not an expert, but it looks like a lot of farmers and people living in small towns are going to be pissed.”

Why would they be pissed?

[don-o]

Thanks for posting that. Very informative

[Red_Devil 232]

Yep. And my min. should have been a second. And my cubit should have been cubic. I had just been reading one of the end times threads.LOL

[bboop]

I thought floods brought that wonderful silt that makes the farmlands so rich? Too much of a good thing, perhaps.

[muawiyah]

There's this storm over Indianapolis ~ says there are 2 more weeks of rain. Same with Columbus, Louisville, St. Louis, Evansville, Nashville, ...... all through the upper reaches of the Mississippi/Ohio/Tennessee watersheds.

What do they do when they run out of design capacity in early June?

Can we get a hurricane too?

This may not be over and the river may jump anyway!

[Past Your Eyes]

Hey, it’s only farm land. That’s not important is it?

[meatloaf]

Thanks for posting that. The Corps recently started releasing water from reservoirs in WV. After seeing the graphic, I understand. I never knew the Ohio had the capability to flow that much water.

Does that mean the system North of Cairo is not up to snuff for major flooding events?

[muawiyah]

That's the Nile. The Huangho (Yellow River) in China is so laden with silt it builds up the bottom and you get devastating floods when the river shifts to a new channel. The Mississippi does that too.

Silt also comes in different qualities ~ some of it you don't want around.

Do not confound what happens with the big rivers with the more localized movement of top soils in small stream basins.

[AGreatPer]

I just don't understand living in any flood zone.

Have had 4 homes in my life, all on top of a big hill.

[okie01]

The distance to the Gulf via the Atchafalaya is half that of the main river channel.

And, someday, Morgan City will rise out of a historic flood...and become the next N'awlins.

Had a good coonass buddy from Morgan City. He told me that everybody in town knows its going to happen...some day.

But nobody wants to be the next N'Awlins. But a big Lafayette...???