TampaRandy created this aerial tour of southern Louisiana. It covers the area between Lake Ponchartrain to the Mississippi River. Pontchartrain is a brackish lake which is part of the river's delta. It sits north of New Orleans, and flooding from the lake caused catastrophic damage to New Orleans following Hurricane Katrina in September, 2005. It's a very large, shallow lake, with an area of about 1.6k square km (about 630 square mi.) but an average depth of only about 4 meters (around 12 ft.).