New Orleans - Levee Check

Even without a hurricane, New Orleans has cause for concern for flooding this spring.

Excessive snows in the north have raised the Mississippi and put locals on alert.

Recent heavy rains in the Midwest, combined with the last melting winter snows, will swell the Mississippi River to an expected crest at 16.5 feet in New Orleans by April 9, high enough to place local emergency officials on guard for potential river levee problems.

The crest will be about half a foot below the point designated as official flood stage at the Carrollton gauge in New Orleans, although a combination of levees and floodwalls protects the city to 20 feet at that location.

I went down to check out the riverbank outside the levee near the Army Corps of Engineers complex. The levees in question this time are not the Pontchartrain and canal levees that breached during Katrina, but the river levees - which are much closer to my house.

What I saw - the photos shown here - stood in stark contrast to the far lower water level I documented in the same place two months ago.

While it's probably not unusual for the season, the water has risen multiple feet since my last visit to the spot. The series of pilings is dramatically underwater, as is the little tree island (the two trunks seen below sticking out of the water farthest out). More than half the rope swing is now floating on top of water.

















Farther upriver near Harahan, the waters of the Mississippi have noticeably risen, passing the treeline along the banks and creeping in amidst debris to a point where they now lap the levee itself.


















I also noticed a somewhat disconcerting point as I read the Times-Picayune article:

The 11-foot mark also means contractors must stop heavy-duty pile driving within 1,500 feet of the levee unless a district or the corps gives special permission. Without a variance, contractors can use only single, non-vibrating hammers.

A Phase 2 alert is triggered at 15 feet, when all forms of pile driving are prohibited within that safe zone, and corps flood-fighting teams join levee district teams to double the river surveillance.

The article does not state how high the water is at present, but it hit Phase 1, 11 feet, on March 11. It's expected to hit 15 feet on March 28 (based on a non-conservative assumption of no more bad weather upstream). So we're probably somewhere around 13 feet assuming a relatively steady climb.

My concern stems from the use of a large industrial pile-driver near the Tchoupitoulas Wal-Mart in recent days. I'm not certain if the site just north of the Wal-Mart is within the 1,500 foot radius from the river, but it seems reasonable to estimate that it is. I'm not sure what type of pile driver is being used, but if it's something other than a single non-vibrating hammer, it should have been barred from use as of March 11. Even if it is a non-heavy duty pile driver, it too will likely need to be barred from use by March 28 if Phase 2 is reached. And that's assuming there's no variance permit issued by the Corps.

It might be nothing, but it's something to look into further, and something I plan to keep an eye on moving forward.

As much as it might be an inconvenience to the developers, I'd sooner err on the safe side and refrain from subjecting the entire city to 1927 reprised.

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