"God promised Noah he would never destroy by flood again."
He does keep His promises. However New Orleans and the Gulf area are not all flesh and all the earth. He meant he would not use a flood to punish all of civilization as an all encompassing final judgement. Read it Genesis. Words mean things. You are really mincing hairs here.
Genesis 9:9-12
9 "Behold, I establish my covenant with you and your descendants after you, 10 and with every living creature that is with you, the birds, the cattle, and every beast of the earth with you, as many as came out of the ark. 11 I establish my covenant with you, that never again shall all flesh be cut off by the waters of a flood, and never again shall there be a flood to destroy the earth." 12 And God said, "This is the sign of the covenant which I make between me and you and every living creature that is with you, for all future generations.
Ridiculously narrow interpretation.