re: Mississippi River Flooding - Links & Pictures in 1st Post

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Everyone is worried about the 70/30 split at ORCS, but they seem to fail to realize that going over 30% at ORCS is only possible up to capacity, and if capacity is 620K cfs, then any flow rates over 2,066,666 cfs will actually cause the ORCS to be operated BELOW 30%. At 2,345,000, it would be operated at 26.4%/73.6% Atchafalaya to Mississippi.


I think that is right...

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I believe you have it right. After reading and studing all these pages of posts, I think I have the gist of what will happen.

However, It shows that the river rising is slowing up in the coming days, yet the cfs of water is steadily increasing(slowly). Is that because of filling the river\__/?

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It's not a 70/30 split between ORCS and MR. It's a 70/30 between the MR and AR regardless of how it gets there. If they have to send 20% through the ORCS and 10% down the Morganza spillway, there is your 70/30 split.

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Not sure about that. The split comes from the legislation that authorized the ORCS. If you want to look at it, it is Public Law 780, 83rd Congress. That is the Flood Control Act of 1954. The Morganza was built under different legislation.

According to the Project Design Flood plan, they will put a combined 44.8% of Mississippi River water down the Atchafalaya, 620 kcfs through ORCS, and 600 through Morganza.

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It's not a 70/30 split between ORCS and MR. It's a 70/30 between the MR and AR regardless of how it gets there. If they have to send 20% through the ORCS and 10% down the Morganza spillway, there is your 70/30 split.

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So at the 1500 kcfs approach mark that the MR reaches at BR, that is when the MS/ORCS will be activated. If there is a higher flow down the MR, will the COE make an adjustment to keep it at a 70/30 split thereby sending more water down the AB.

Old River Lock to close Thursday, May 12

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NEW ORLEANS, LA – Due to high water on the Mississippi River, the Old River Lock will be closed to navigation starting Thursday morning, May 12.

The recess for the lock’s gate arm machinery, which is used to open and close the miter gate, will begin flooding when water elevations reach either 63 feet at the Old River Lock or 62.5 feet at Red River Landing. To prevent damage, all electrical equipment needs to be uninstalled and removed, and the recess needs to be sandbagged before that elevation is reached.

The lock will re-open once the river recedes below 62.5 feet at Red River Landing.

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Currently in Phase II on both Atchafalaya and Mississippi Rivers.

NWS current prediction that indicates a crest at 19.5 feet in New Orleans,
Red River Landing at 65.5, Baton Rouge at 47.5, and 9.5 in Morgan City.

Bonnet Carre has opened 72 bays. The spillway tile gage today was reading
22.5 feet , water is over the concrete weir and through the needles on all
350 bays. St. Charles Parish Highway 12 (SC 12) has been closed to traffic
by
St. Charles Parish Public Works.

Old River has minimal water passing through the needles of the Overbank
Structure. Lock will be closed to navigation beginning 12 May 11 to remove
the electrical components to the gate arm machinery and sandbag the
machinery
recess.

Morganza has a significant amount of water against the structure, gage
reading 56.15. Monitoring potato levee and seepage area near north abutment
of Morganza Control Structure. To date, we have sandbagged approximately
4,138ft of the required 4,500ft section.

Structures in the lower Atchafalaya including the Charenton Floodgate, East
and West Calumet Floodgates, and Bayou Sorrell Lock are being fortified with
interim measures to protect from higher river stages.

Levee slides are being evaluated and temporarily repaired as needed.

Seepage and sand boils are prevalent throughout the area, we continue to
inspect, responded, and monitor closely.

Navigation continuing to get too close to the levee system, still an issue.

Moved DTOS units to Baton Rouge and Morgan City.

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The latest from the NWS...

HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE NEW ORLEANS LA
949 AM CDT WED MAY 11 2011

...CONTINGENCY FORECASTS FOR MISSISSIPPI AND ATCHAFALAYA RIVERS...

SIGNIFICANT RAINFALL ACROSS THE MIDDLE MISSISSIPPI AND OHIO RIVER
VALLEYS OVER THE PAST MONTH HAS LED TO HISTORIC...AND IN SOME
CASES RECORD BREAKING...RISES ON BOTH RIVERS. AS THIS WATER MOVES
DOWNRIVER...SIGNIFICANT RISES WILL OCCUR ALONG THE MISSISSIPPI
AND ATCHAFALAYA RIVERS THROUGH SOUTHEAST AND SOUTH CENTRAL
LOUISIANA.

ALL OF THE LATEST RIVER FORECASTS FROM THE LOWER MISSISSIPPI RIVER
FORECAST CENTER ACCOUNT FOR A FULL OPENING OF THE BONNET CARRE
SPILLWAY LOCATED IN ST. CHARLES PARISH. THE ARMY CORPS OF ENGINEERS
WILL CONTINUE TO OPEN UP MORE GATES OF THE BONNET CARRE SPILLWAY
TODAY WITH EVENTUALLY ALL 350 BAYS EXPECTED OPEN BY WEEKS END.
THE OFFICIAL FORECASTS CURRENTLY DO NOT ACCOUNT FOR A POSSIBLE
OPENING OF THE MORGANZA SPILLWAY IN POINTE COUPEE PARISH.
HOWEVER...THE RIVER FORECAST CENTER IS PROVIDING CONTINGENCY
FORECASTS WHICH ACCOUNT FOR A POSSIBLE OPENING OF THE MORGANZA
SPILLWAY.

THE TABLE BELOW LISTS BOTH THE OFFICIAL FORECAST AND
THE CONTINGENCY FORECAST FOR ALL FORECAST POINTS ON THE
MISSISSIPPI RIVER IN SOUTHEAST LOUISIANA AND ATCHAFALAYA RIVER.

IT SHOULD ALSO BE NOTED THAT WHILE THE OFFICIAL FLOOD STAGES ARE
LISTED BELOW...MOST POPULATION CENTERS ARE PROTECTED BY FLOOD
CONTROL LEVEES TO MUCH HIGHER LEVELS.

THE CONTINGENCY FORECAST PROVIDED FOR THE OPENING OF MORGNAZA ONLY
ACCOUNTS FOR A 50 PERCENT OPENING OF THE SPILLWAY.


FORECAST POINT FLOOD FORECAST WITH CONTINGENCY WITH
STAGE MORGANZA CLOSED MORGANZA OPEN

RED RIVER LANDING 48.0 65.5 63.5-64.5
BATON ROUGE 35.0 47.5 45.5-46.5
DONALDSONVILLE 27.0 36.0 34.0
RESERVE 22.0 28.0 25.0
NEW ORLEANS 17.0 19.5 17.0

SIMMESPORT 47.0 50.0 50.0
MELVILLE 41.0 40.0 40.0
KROTZ SPRINGS 37.0 35.0 35.0
BUTTE LA ROSE 25.0 25.0 29.0
BAYOU SORREL LOCK 12.0 14.0 21.5
MYETTE POINT 15.0 14.5 19.0
MORGAN CITY 4.0 9.5 12.0-13.0

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That is going to be bad. I am hearing that Conrad has closed its yard on the river.

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They moved everything to Amelia last week and earlier this week, and moved the prop shop to Houma....they built this huge levee around their yard on the river, its quite amazing

My butthole just puckered up

The COE needs to stop dancing around the issue and officially announce that they will be opening Morganza, and when. They are causing needless stress to everyone by the incessant "hinting."

City of Morgan City Facebook page has pics from today of the water on the wharf.