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Day 3: New Orleans Topography and Geography

in geology, hurricane katrina, new orleans

I’ve received quite a few emails from friends and scared evacuees wondering about their friends and homes back in New Orleans. When all one’s got is CNN TV and a barrage of (good) information from the Times Picayune, one is bound to get frustrated not knowing what to believe.

Before you read any further, keep in mind that there are several different types of damage: flood, wind, downed trees, structural damage, looting of stores. The following deals with Orleans Parish neighborhoods flooded by compromised levees.

In order to keep yourselves from getting confused, go online and find a map of New Orleans with all of the neighborhoods marked, like the one below. Now, for the third dimension, i.e. altitude, divide the portion of New Orleans between the lake and the river into two roughly-horizontal strips that are two bowls within the larger bowl of New Orleans, separated by the Metairie or Gentilly Ridges. See here for a cross-section from the river (by the FQ) to the lake (NO East). Also, Jon just sent me a CNN graphic with another cross-section that illustrates my point.

The upper strip containing Mid City, City Park, Lakeview (west of City Park) and New Orleans East (east of the Fairgrounds) is the northern and lower-lying bowl-within-a-bowl. Uptown, the Garden District, the Central Business District (Superdome, Shell) and the French Quarter are higher.

Disclaimer: The above topographic description of New Orleans is not entirely exact, but it works for the purpose of this exercise.

New Orleans

The higher bowl has not experienced too much flooding yet, mostly because rising water has to cross a small saddle to spill over. This is what we don’t want. However, if a few more levees are breached “pouring hundreds of thousands of gallons of lake water per second into the New Orleans area,” I’m going into the gondola-tour business.

More from NASA’s Earth Observatory.

Please hold while I go lose my coffee.

3 comments… add one
  • CNN has a potentially useful map/diagram: http://www.cnn.com/interactive/weather/0508/map.new.orleans/frameset.exclude.html

    The video “Water pours into New Orleans” on http://www.cnn.com/video (sorry, I can’t figure out how to link directly to it, JavaScript be damned) seems to show the reporter standing hip deep in water on Common St. But, I don’t know exactly when it was filmed (CNN claims to have posted it 01:31 pm, Aug 30).

  • Paul Orlowski

    Hey Maitri:

    Good to hear your and D are okay. It must be tough mentally. If we can do anything for you, just let us know.

    Thank you for a little background on the city. I still don’t know the parish system yet, but at least I have a better idea of what people are referring to when they mention a location.

    Stay safe,
    Paul

  • Edward Polanski

    Is New Orleans above or below sea level? Some say it is below sea level, some say it is mot. I’m confused.

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