This says 2014 population was down 7.7% post-Katrina.
I found two sites which are recording the level of the Mississippi River in New Orleans, from weather.gov and the US Army Corps of Engineers. These screenshots are of the most recent results:
And here's a nice storm track.
Much of the area around New Orleans is now 1½ to 3 meters (4.92 to 9.84 feet) below mean sea level, according to a 2003 study by the US Geological Survey. Scientists found that the ground in the area was sinking at a rate of 1 centimeter a year.
That continual sinkage, combined with rising global sea levels due to the climate crisis, meant New Orleans would probably be between 2½ and 4 meters (8.2 to 13.12 feet) below sea level by 2100.