Can you tell me the geologic reasons why the flood occurred in New Orleans after hurricane Katrina?

Answer 1

It was mostly caused by flaws in the design, construction, or maintenance of the levees
.
Geologic reason
The city is below sea level.

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.



In 2005, as a result of Hurricane Katrina, there were extensive failures of the levees and flood walls protecting New Orleans, Louisiana and surrounding communities. Subsequent extensive investigations were conducted by civil engineers and other experts in an attempt to identify the underlying reasons for the failure of the hurricane protection system.

The Mississippi River-Gulf Outlet Canal ("MR-GO") breached its levees in approximately 20 places, flooding much of New Orleans East, most of Saint Bernard Parish and the East Bank of Plaquemines Parish. Major levee breaches within the city of New Orleans occurred on the 17th Street Canal, the London Avenue Canal, and the wide, navigable Industrial Canal. Approximately 80% of the city of New Orleans was flooded.[1]

Three major breaches occurred on the Industrial Canal; one on the upper side near the junction with MR-GO, and two on the lower side along the Lower Ninth Ward, between Florida Avenue and Claiborne Avenue. The 17th Street Canal levee was breached on the lower (New Orleans West End) side inland from the Old Hammond Highway Bridge, and the London Avenue Canal breached in two places, on the upper side just back from Robert E. Lee Boulevard, and on the lower side a block in from the Mirabeau Avenue Bridge. Flooding from the breaches put the majority of the city under water for days, in many places for weeks.

In the aftermath of Hurricane Katrina, engineers investigated the possibility that flaws in the design, construction, or maintenance of the hurricane protection system lead to the failures, and thus much of the flooding. Some investigations point to the possibility of a weakening of the soil beneath the foundations of the flood walls due to storm water, which would indicate that a major design flaw made during the construction of the levees had been a major cause of the failures due to the storm.[2]

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Answer 2

Because New Orleans is mostly below sea level - one of the worst possble places on Earth to try and maintain a city.

Answer 3

Failure of the state and native government to apply the federal money presented for maintenance of the pumps and the levies. the money strengthen into spent on liberal foolishness rather. So the pumps and the levees failed. ensuing in huge flooding. The blood is on the palms of mayor Noggin and the different corrupt politicians of Louisianan.

Answer 4

There's a canal running through the city with its water level higher than the level of the ground where the houses are.

This is a really dumb way to build a city!

Answer 5

The city was below sea level and the levees just broke.

Answer 6

Bury a bucket in your yard, place one above ground, and squirt a hose at them.

The city's under sea level. That's why their graveyards have no headstones, just those above-ground crypts. It's not long before you reach water!