Tuesday, September 4, 2012

Inspectors examine levees in New Orleans, post-Isaac

Pete Spotts in the Alaska Dispatch via the Christian Science Monitor: Hurricane Isaac has come and gone. Floodwaters in southeastern Louisiana are receding. For Chris Gilmore, it's time to take initial stock of how his segment of a $14.5-billion, 133-mile defensive wall of earth, steel, and concrete preformed in the first real-world test of post-Katrina improvements in flood protection for New Orleans and portions of surrounding parishes.

Isaac was a minimal hurricane when it made landfall overnight Aug. 28-29. But its large size and excruciatingly slow motion – at one point stalling for hours over the southeastern part of the state – built a surge whose height here at St. Bernard Parish, estimated at between 14 and 15 feet, rivaled the height of the surge Katrina delivered.

The view from the levee top reveals large patches of dead-wood debris lying along the levee's base like so many casualties of a siege assault. Behind the levee and the new pair of massive steel floodgates that close across the four lanes and center median of Louisiana State Road 46, boats on trailers, RV trailers, and even trailers from 18-wheelers are parked along the highway shoulders. They belong to residents who live beyond the levee and who sought its protection for their hard-earned assets.

So how did this segment hold up? "It looks really good," pronounces the US Army Corps of Engineers' Mr. Gilmore, senior project manager for the St. Bernard Parish portion of the federally funded upgraded flood defenses.

Indeed, so far the most significant levee damage has come from wild hogs, who root around for worms and insects after heavy rains. These "hog holes" will require quick attention. They can accelerate erosion of a levee's earthen base.

Although inspections are still under way, the initial reaction to the post-Katrina improvements to the levees, as well as to the pumping systems that drain water from New Orleans into canals that feed into Lake Ponchartrain, is that they worked as advertised....

Levee repair in New Orleans' Industrial Canal after Katrina, shot by Stephen Marchetti, Wikimedia Commons via Flickr, under the Creative Commons Attribution-Share Alike 2.0 Generic license

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