Katrina :: Storm Effects
Return To NewOrleans/HurricaneKatrina Homepage
Effects of the Storm :: Hurricane Katrina :: Below Sea Level
New Orleans, much of which sits below sea level, is surrounded by the Mississippi River to the south, Lake Pontchartrain to the north, and the Gulf of Mexico to the east. Construction of the levees between New Orleans, the River, and the Lake began in 1879. The earthen barriers were originally erected to prevent damage caused by seasonal flooding and to allow the city to expand beyond the natural levees on which it had been initially constructed.
http://en.wikipedia.org/wiki/Effect_of_Hurricane_Katrina_on_New_Orleans
Continue below...
Below Sea Level
New Orleans, much of which sits below sea level, is surrounded by the Mississippi River to the south, Lake Pontchartrain to the north, and the Gulf of Mexico to the east. Construction of the levees between New Orleans, the River, and the Lake began in 1879. The earthen barriers were originally erected to prevent damage caused by seasonal flooding and to allow the city to expand beyond the natural levees on which it had been initially constructed.
Unfortunately, the levees interfered with the normal process of the River depositing sediment and building up the land of the delta marshlands during the periodic floods. Interrupting a process that created the land of the Mississippi Delta over the course of thousands of years caused the land to dry out. In turn, the swampy lands of Southern Louisiana shrank like a sponge, the land began to sink and entire barrier islands disappeared as the land of the vast delta slowly settled into the sea.
The subsidence of the land of southern Louisiana can be attributed to one or more of the following:
the leveeing of the Mississippi River,
the pumping of ground water from under the city,
the failure to address the environmental impact of development on the Mississippi Delta,
environmental damage caused by oil and gas production,
the failure to maintain or upgrade the levee and flood wall system despite many studies that warned of impending disaster. [1]
Interestingly, the land of New Orleans and the surrounding communities was not below sea level when the communities were built. The area began to sink precipitiously only after the current levee system was erected in the 1940s and 1950s and accelerated when the shipping canal flood walls were completed in the mid 1960s.
Shea Penland, a geologist at the University of New Orleans and contractor for the U.S. Army Corps of Engineers, which maintains the levees, attributes one third of the land subsidence to the large number of canals through the delta. Barge traffic and tides erode the earth around the edge of the canals, and salty Gulf water seeps in along them, slowly salinating the ground and killing the vegetation that helps hold the land together. [2]
http://en.wikipedia.org/wiki/Effect_of_Hurricane_Katrina_on_New_Orleans
Storm Effects Homepage
Website Homepage
