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

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From your article the Corps is quoted as saying the river would be flowing at 1.9 million cfs at Red River Landing at crest. A previous article quoted an estimate of 2.1 million cfs for the river at Natchez at 60' levels. Obviously this is going to be different because of the river width, depth,bottom contour, etc.

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River width, depth and contour have nothing to do with the different flows. There are areas along the river between Red River Landing and Natchez where water goes into storage. Basically the water leaves the channel and enters an area with little to no downstream flow. This causes the downstream flow to decrease. There is also an area between RRL and Baton Rouge that puts 50kcfs to 100kcfs into storage. So the flow at BR will be slightly less than at RRL.

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Does anyone know how accurate these estimates really are, or are they simply blind guesses at this point as it pertains to flow?

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The estimates are quite accurate. USGS/CORPS uses a rating curve to detemine flows. It is a stage(level)/discharge(flow) relationship. As the stage increases so does the discharge.

Discharge measurements are made by driving from bank to bank via boat with a current profiler. We make measurements at different levels and plot the discharge vs level to determine a rating equation.

They are predicting the river level in Red River Landing to get to 65.5 ft so the rating give a discharge of 1.9 million.


We made a measurement yesterday morning in BR and measured 975kcfs. Take a look at the discharge for yesterday morning at our gage.

LINK

We were within the allowable error of the measurement. So our rating is accurate.

BTW this rating was developed during previous floods

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We made a measurement yesterday morning in BR and measured 975kcfs. Take a look at the discharge for yesterday morning at our gage.

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I don't understand those numbers, but the water was moving quickly today when I was there. How much faster is it expected to move?

If I'm not mistaken, I believe it is supposed to get to about 1.5mil kcfs. That is what I gathered from following this thread

The levees in BR were designed (or, more accurately(?), are rated to safely handle) for a flow of 1,500,000 cfs. If the flow is projected to exceed this amount at BR, it "triggers" the opening of the Morganza.

A flow of 1,250,000 cfs triggers the opening of the Bonnet Carre.

Scottie what do you think will be the damage to MC when they open the morganza next week?

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Scottie what do you think will be the damage to MC when they open the morganza next week?

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Scottie what do you think will be the damage to MC when they open the morganza next week?

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Hard to say. The only thing anyone has to go on is the '73 flood. They are predicting 9.5 ft without Morganza open I would say 10.5 to 11.5 with it open.

Not exactly sure but that would put about 3-4 feet of water on the flood wall at Front Street and would probably cause some flooding in the areas out side the protection levee.

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a levee supposedly just broke in Dyer County Tennessee

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I did a quick google search and all I see are stories about a levee that was intentional breached last week. Have you got more details?

Memphis news has been reporting about that levee breaking.. Its not getting any better.. Everyone worry about Osama better take note the Mississippi river is not happy.. A ton of people are ignoring the flood warnings around TN i hear..