The Army Corps has their own language; such as overtopping a levee is not a levee break.

Dewatering is pumping water out
Rewatering is a flood.

Just the 9th ward is under waist deep water so far but no remedy can be attempted for at least 20 hours.

So we have a small 30 foot overtopping resulting in a rewatering of the 9th ward which is already depopulated.