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On exactly the seven-year anniversary of Hurricane Katrina (Aug. 29), Tropical Storm Isaac is heading toward the mouth of the Mississippi River, likely to make landfall as a Category 1 hurricane, and possibly as a Category 2, with wind speeds up to about 100 m.p.h. Click on the diagram above, drawn by the excellent graphic artists at the Times-Picayune, to see details of the $14.6 billion storm protection system that has been put in place by the Army Corps of Engineers since 2005. Click NOLA.com to see periodic updates by environmental reporters Mark Schleifstein, Bob Marshall, and others. More details to follow.

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