Well, from what I've read, the pumps are the highest priority and have been upgraded in recent years. However, if the levees are overtopped and the bowl fills, the pumps will go down. Appears that might also happen if a breach fills the bowl. Looking at maps on the Army Corp of Engineers' website, they show the levee heights to be 11' on the west, rising to 17' at the northwest corner on the lake, then varying between 18' and 13' all along the north and east. Am guessing the variance is from subsidence? Similar numbers to the south, but because of the complex of levees protecting the south shore communities, perhaps that would blunt the wave action and some of the direct surge from a south approach? Just speculation on my part, and I have no idea how high the storm surge would be on the city's north shore from topside winds coming from the north as the eye passed to the east. Would think it would be lower than the predicted direct surge, which is pushed not only by the winds but also the storm's momentum, but the flip side is how much would the piling up of all that water in the small area of the lake exacerbate the wind driven surge? I have no idea, and haven't read any predictions on that, other than the simple conclusion that if the levee is 13', 14' of surge will overtop it.
Evac orders for Mobile in a few mins per FOX NEWS
There's a "slosh-effect" too. Regardless of the direction the storm comes in, the water in the lake will be pushed one way and then slosh back contra-coup style when the storm passes. Unfortunately, the storm will work with the natural tendency of the Miss. River to change course, as well. It's been held back by the levees for about 300 years and if/when the big one hits just right, the Miss River may very well assume whatever course it was meant to be on by now. Whether there is great loss of life or not, the financial devastation of losing the Port of New Orleans indefinitely would be incredible.
Just prior to Betsy making landfall in 1965 the Army Corps of Engineers blew the levee that protected the Eastern part of New Orleans and Chalmette from the waters of the Mississippi River Gulf Outlet. They were trying to protect the city proper from major flooding. It worked. Yes, there was flooding within the city but not nearly as bad as it would have been.
Large areas of the Eastern part of New Orleans and Chalmette were flooded, especially those homes close to the Gulf Outlet but "downtown" was spared, for the most part. The levee actually would have acted like a funnel to direct the waters to the city. Blowing the levee alleviated more flooding and spread the water out over a greater area.
The Mississippi River Gulf Outlet is NOT the Mississippi River. It is a channel that was dug from New Orleans straight to the Gulf.....not like the snake that is the river. The river is a 112 mile snaking nightmare for navigators. The Gulf Outlet is only 76 miles and a straight shot. Good for shipping but also disastrous when dealing with a hurricane.
( I put "downtown" in quotes because in New Orleans "downtown" is called "uptown." If you say "downtown" in New Orleans then they'll look at you like you are insane. "Downtown" is the "shabby" part of town. ) :-)