Mythbusters: The Bible

[Stig]

I don't believe in any god at all, everything written in either bible or koran or whatever can be proven wrong. Some are easy, some more difficult, but we can bust all myths

[Kraxis]

The end of the last ice age saw a rise in the waterlevels that was downright scary. For isntance the entire North Sea (between Denmark, England/Scotland, Germany/Netherlands and Norway) was one big grassplain. Now it is gone. But people could perhaps have culturally remembered thetime when they could live in places now under water.
That can explain the more general stories, however it happened over a long time, so the Flood as we know it doesn't really fit that well.

However, the Black Sea fits the bill.
Before the Med. broke through the Bospherous, the Black 'Lake' was a mere third of what it is now. And the waterlevels were as much as 100 meters delow sealevels.
I'm sure you have heard of the great Ukranian plains, flat flat flat... stretching forever. Well the land that is now occupied by the Black Sea to the north of the 'lake' was just like that. So it has been estimated that people could have gone to bed with no water in sight (might not even have known of a great lake to the south), then in the morning there would have been water around their feet for as far as they could see.
Such a thing would leave a huge impact on the people that experienced it. What could be doing that? Where would the water come from? Which direction is land?
Who would survive? The few people with boats, naturally, as the footchuggers wouldn't be able to outpace the water.

Bob Ballard actually found a settlement on the sea floor in search of a Byzantine shipwreck (talk about huge luck for the man). Proving that people did live there. And the find eevn seemed to indicate that it might have been one that experienced the flood, as it still had things lying around and the foundations of the walls were visible (no time for the more harsh abovewater environments to wear it down).