I doubt this position is going to be particularly welcome, but here it is anyway:
Flood myths are common, and in Genesis we have the Hebrew form of the flood myth--almost certainly derived from the near eastern flood myth such as we see in the Epic of Gilgamesh.
What's more important is what was the reason for the writers/compilers of Genesis have for including the story? How does the story fit within the overall narrative of Genesis--and what is Genesis, as a text, really about or what is its purpose as a text?
To that end I propose:
The book of Genesis has a two-fold purpose,
1) It is a book of the Torah, or The Law, those five books which served as the central corpus of ancient Jewish religious life understood to be instruction to them from God. Genesis is a teaching text, the same way that Exodus, Numbers, Leviticus, and Deuteronomy are teaching texts.
2) Genesis serves as a kind of narrowing prologue that gets us from the big picture of the world to the smaller picture of Israel in the Exodus. And as such narrows in scope from creation, to Adam, to Noah, to Abraham, to Jacob, and then we get to the Exodus--the central story of Israel's religious and national identity as the people of God.
I want to focus on the first, that Genesis is a teaching text. So the story of the flood must be understood first as conveying a lesson, what is the lesson we can learn here?
In the story we have God apparently quite angry with the wickedness of mankind, so much so that He opts to wipe them out and start fresh--so God chooses one man, Noah. Noah and his family will be the fresh start, a righteous start after God wipes the slate clean by destroying nearly everything (global or local is unimportant as the ancients who wrote and read the story wouldn't have had a comprehension for a global anything and such would be entirely beside the point). And yet, when all is said and done, the flood waters recede, and Noah and his family step foot on dry earth we almost immediately find Noah getting drunk and passing out naked, and when his son Ham comes upon him Noah curses Ham's son Canaan. And the next story we come across involves people coming together, in their arrogance, to build a tower to reach heaven, and by the time we get to Abraham how has the flood cleansed the earth? How has Noah or his progeny been any better than what came before? The world is still seemingly broken, human beings are still doing wicked things, and idolatry has run amok. We even get a rather disturbing story about two cities, Sodom and Gomorrah.
So, rather fascinatingly, if the purpose of the flood was to cleanse the world of wickedness and start over with a new righteous humanity, then the flood was a complete and absolute failure.
And here is where I would argue this: The the point of the story is ultimately to say that even should God destroy the world and start over it would not fix anything. The world would still be the same, even if you started over with a new, ostensibly righteous set of individuals, such as Noah and his family.
So what would be a way of bringing healing to the world? Well it might look like God calling a man by the name of Abraham out from the city of Ur, it might look like God delivering a people out from enslavement in Egypt. It might look like what the Prophets envision in their writings, of the world coming to Zion, of the wolf laying down with the lamb, with men turning their swords into plows, and their spears into pruning sheers. It might look like a "new heavens and a new earth".
And for Christians, ultimately, it looks like God coming down into the world in and through a tiny infant named Jesus, who preaches good news about a kingdom where the poor, the hungry, and the oppressed are blessed; where the first shall be last and the last shall be first, and the greatest is our slave. It looks like this Jesus being nailed to a cross and crying out, "Father, forgive them, they don't know what they're doing." And it might look like this Jesus being raised from the dead, and giving the promise of life that is stronger than death, that the world will one day really be made new; not through cosmic genocide, but rather through justice, mercy, and redemption. With the final picture being of a heavenly city descending upon the world, where God and man live together in the world in true peace, and there is a river that brings leaves from the tree of life which is for the healing of the nations. That's what the mending and healing of the world looks like.
-CryptoLutheran