Snip from Guardian UK:
The Louisiana coastline may have been so badly damaged by the hurricane because manmade engineering of the delta has led to erosion of natural defences, according to the American Society of Civil Engineers.
The engineering of the last 100 years that has reworked the Mississippi delta with thousands of miles of levees and flood barriers to protect communities and aid navigation, has also disturbed natural barriers which traditionally prevented storm surges and protected against hurricanes, says the society.
"Human activity, directly or indirectly, has caused 1,500 square miles of natural coastal barriers to be eroded in the past 50 years. Human activity has clearly been a significant factor in coastal Louisiana land losses, along with subsidence, saltwater intrusion, storm events, barrier island degradation, and relative sea level changes," the society said in a paper last year.
It warned that "New Orleans and surrounding areas would now experience the full force of hurricanes, including storm surges that top levee systems and cause severe flooding as well as high winds".
The damage done this time may be also linked to White House cuts in funding for hurricane defence to pay for homeland security terrorist defences.