Upper Mississippi flooding

Two more articles

Here are two articles from the St. Louis Post Dispatch regarding blowing the levee up:
Flood poses dilemma
Judge OKs Army Corps to break Missouri levee

So when was the last time this spillway was open, or Morganza, for that matter? And bear in mind, the snow hasn't started melting in the mountains. In fact, it is still accumulating.

Bonnet Carre Spillway

The last time this was opened was 2008. It has been opened 8 times since it was built in 1932. It is really quite an interesting operation. There are 350/360 'bays' or sections with wooden timbers. They roll a crane along the top and pull timbers up individually to let the water from the river flow into the spillway. As this article mentions, only a portion of the bays are opened each time. You can see this structure as you drive in from the west on I-10, and during normal times, you can drive right through the spillway area on a local road. The determining factor to open it is not the height of the water, but rather the cubic flow per second, but of course that is influenced by the height. 17 feet is the standard level when this is considered. The levees are 25 feet high, but they leave leeway for wind and traffic action so the levees aren't overtopped. Bonnet Carre Spillway likely to open as levee inspections intensify along Mississippi River | NOLA.com

When does the seawall gates at Toulouse Street and St. Peter Street get closed? What stage of the river closes the NATCHEZ down due to the high water?

I remember reading an article about the declining state of the Morganza Spillway. It said that if repairs were not made, it would not hold back the river much longer. It also stated that the Mississippi would then change course and convert the Achafalaya basin into the main channel. This would cause great devastation in the basin. But it would eventually be a boon to New Orleans as it would become a saltwater estuary with no silting. Has anyone else heard this or is it just some half-baked theory?

Flood gates in the FQ

Those gates are put in only for hurricanes, since the river level is controlled to not top 17 feet, which is well below the top of the levee. At 17 ft. the NATCHEZ' guard is just about even with the wharf decking. I'm not aware of any particular stage that stops her cruises, I've worked on her at 17 ft. It would be a matter of a combination of things like wind, rain, and/or fog on top of the high water that would affect individual cruises. Doc has always said that the most dangerous stage is about 13 feet, with more eddies and uncertainties to deal with than at higher stages. And of course, the NATCHEZ has enough power and steering to handle the NOLA harbor conditions. Back at the '06 Tall Stacks when the river rose overnight, the NATCHEZ was prepared to go out - those conditions were nothing compared to NOLA, but the lesser powered boats didn't want to risk it. After one cancelled cruise, the NATCHEZ resumed and I believe most of the others did later that day.

All clear to go ahead:
Associated Press | The Register-Guard

Thanks, Judy. Come to think of it, while standing at the NATCHEZ's landing you do look down on those seawall gates.

You are referring to the Old River Control Structure. The Morganza spillway is entirely different. The Control Structure is an actual man-made barrier that allows overflow from the Mississippi into the Red River and Atchafalaya basin and is also supposed to prevent the Mississippi from going that way, as it most certainly wants to do. This structure has for some time been compromised by the currents of the Mississippi. It is an ongoing battle to keep it from failing and allowing the Mississippi to change course and flow down the Atchafalaya. It is not a half-baked theory that it could happen. It could really happen, but I don't think the navigation from there down the rest of the Mississippi would be to the advantage of New Orleans or Baton Rouge if it did. Lots of scenarios exist as to what it would be like and how it would affect the region if the structure failed. Only time will tell.

to the Supreme Court

Missouri filed for an injunction with the US Supreme Court today. Judge Samuel Alito was given the case. An injunction would prohibit the detonation. Missouri takes levee battle to U.S. Supreme Court - CNN.com

Meanwhile, up here we've dropped 3.6 feet from last Saturday's crest. Some roads are still closed, but we're close to normal other than ground right next to the river still being underwater.

Supreme Court decision

Justice Samuel Alito has refused an injunction, so the Corps levee blowing up has clear sailing legally.