If water is waist deep around the Super Dome, isn't that pretty close to the French Quarter?
I have a feeling it will take several hours for water to reach an equilibrium inside the bowl. IIRC, there is a lot of massive highway structure between the dome and FQ. I bet we hear of rising water in the quarter soon as water seeks the lowest points.
If my memory serves me right you see the superdome off to the left of the freeway as you come into the city. I think it's on the other side of downtown from the French Quarter.