It has been one year since Hurricane Katrina crashed into New Orleans.
And while the Army Corps of Engineers says it has almost completely restored the levees to pre-Katrina levels, there is still concern they may not withstand a hurricane.
Dr. Billy Edge, a Texas A&M engineering professor, serves on a national committee to find out what must be done to protect the area from a future storm.
One year ago, the category three hurricane killed at least 1,300 people, caused close to $100 billion in damage, and changed lives forever.
New Orleans was devastated during the aftermath of the storm when the levees were breached, and crews have put in five years of work in just 12 months repairing them.
Federal officials say the levees will now withstand another storm, while others disagree.
"We do know that if everyone evacuates it can be safe, but we don't know how much damage will occur," Dr. Billy Edge, head of the Coastal and Ocean Engineering Program at Texas A&M University said.
Edge serves on the New Orleans hurricane protection system committee, and he is only one of several A&M faculty members studying what went wrong with the levees during Katrina.
"They were over topped and there was not a provision made on the backside for correcting against the over topping and erosion that was caused by the over topping," Edge said. "Once the erosion occurred it weakened the structural stability."
Since then, Edge says, the levees have been put back together.
Some are not as vulnerable as before, others are close to how they were.
"The St. Bernard levee is at the same elevation it was previously," Edge said. "That's the one that was over topped pretty heavily so that's still a vulnerability in the system."
So what if another storm is lurking around the corner?
Some experts say New Orleans could withstand another category three hurricane, but Edge says it's hard to determine the damage regardless of the storm's size.
"The risk to people to rebuild next to the levy is really unknown," Edge said.
And it could be the unknown that is keeping half of the population of New Orleans from returning.