How Katrina Devastated New Orleans

Contrary to popular belief, New Orleans was built on a "high spot."  The older parts of the city, such as the French Quarter, still remain above sea level and it rarely floods there.  It's the "newer" parts of the city that floods.  As the "Big Easy" grew, it required the swampland surrounding the city to be drained so development could occur.  Draining out the swamps caused those areas to sink below sea level and as a result, these areas are in a depression.  When it rains, flooding becomes a big issue, for there is no place for the water to go.

To solve this problem, New Orleans dug canals that ran north and would channel the water out to Lake Pontchartrain.  These canals were pretty high so they could have a downward slope allowing the flood waters to drain into the lake.  In order to bring the water up into these canals, New Orleans would employ several humongous pumps, which would activate by rainwater.  These canals had levees to prevent the water from re-flooding the city and it was those levees that failed in August 2005 when Hurricane Katrina made landfall.

When Katrina entered into this country, the eye of the storm passed to the east of New Orleans.  The levees on the Mississippi River that flowed in the south remained in tact.  The city assumed that it was spared yet again; but because hurricanes spin counter-clockwise, the precipitation and the winds blew to the west and down to the south into New Orleans after it passed by.  The storm surge did not come from the Gulf of Mexico as expected.  The danger came from Lake Pontchartrain in the north, hours after Katrina pounded the Mississippi Gulf Coast.

Water from Lake Pontchartrain went up the canals overwhelming the levees there.  For one thing, the ditches flooded over and the levels rose above the levees and the deluge dropped right into the "bowl."  By doing this, the water undermined the integrity of the levees and some of those toppled over as a result.  Others, because of the velocity of the surge, were pushed aside.  Before long, there were holes throughout the system and New Orleans was getting inundated quickly.  By the time authority figures noticed the problem, it was too late.  By then, nothing could have been done to avert the damage.

This is indeed a very unfortunate event as thousands of people died.  It is the greatest natural disaster that ever happened in this country and it is a topic that I shall explore further in future blogs.  There is more that meets the eye here and we all can learn from the mistakes we have made.  Hopefully, a tragedy such as this will not occur again anytime in the near future, or ever.  We can reduce the chances of this re-occurring by paying heed today.  Let's listen to what the Earth has to say.

--GeoJack
March 31, 2012
Fayetteville, AR