As Isaac nears the Gulf coast, there's a mandatory evacuation in place in Lousiana's Plaquemines Parish. Nearly 90% of that parish was flooded during Hurricane Katrina.

Billy Nungesser, president of Plaquemines Parish, talks with Soledad O'Brien on "Starting Point" this morning, sharing what his parish has learned since Katrina and how the city is preparing for Isaac. Nungesser shares his biggest concerns as Isaac nears the Gulf Coast.

"We have two levees that are not in the federal system, the east and west bank and 5 feet on one side of the river, 8 on the other. Storm surge expected to be 10 or 11 feet," Nungesser says. "We're going to see water over tops of the levees and we'll see the storm weaken hopefully and not top the levees, but the way it looks we're going to have water.

Nungesser is also concerned that settled oil from the BP spill could be redistributed on the delicate marsh areas.

"There's so much thick oil on the bottom," he says. "We see it kick up ever for a thunderstorm. So this type of event absolutely will take some of that oil and put it back in the marsh. You won't see the thick oil like during the oil spill. But you can see it, the thin oil through the marsh and it still does affect the wildlife in the marsh. You don't see those birds covered in oil, but any oil is not good for animals out there. So we're real concerned and after this event we'll be out there to check those heavily impacted areas to see how much oil does get kicked up back into the marsh."

Nungesser says one thing that has greatly improved since Katrina is planning and preparation for a storm like Isaac. He says people feel safer since Katrina because they're more prepared.