Tuesday October 5, 2004

Dear Yahoo!:

Why isn't New Orleans under water
since it's below sea level?

Johanna
St. Petersburg, Florida

Dear Johanna:

Strange, but true: the Big Easy is, on average, eight feet below sea level. Tall levees to the north and south keep the Mississippi River and Lake Pontchartrain from pouring into the center of the city. And an intricate system of pumping stations and canals keep the land dry, even after heavy rainfall.

Without this drainage system, much of the city would be engulfed in water. New Orleans occupies swampland created by millions of years' worth of silt deposits from the Mississippi River. As a result, the ground is wet and spongy, and prone to flooding from rainfall and hurricanes.

Ironically, all the pumps, canals, and levees that work so hard to keep New Orleans above water are actually causing the city to sink at a rate of three feet per century. Some scientists predict that by the year 2100, the "City That Care Forgot" will be under water. Does New Orleans have a deep-sea Mardi Gras in its future? Scuba gear or not, it's interesting to ponder.