Since there's no physical evidence to support the kind of world-wide flood being believed in and the only evidence of such a flood is in the Bible and its source documents (eg, Gilgamesh), then obviously belief in the Bible's flood myth would indeed be the source for belief in that flood.
The closest thing to a world-wide flood would be changes in sea level. For example, the last major change happened about 11,000 years ago with the end of the last ice age, when the melting ice cap caused the level of the oceans to rise about 200 feet. Since the Persian Gulf is shallower than 200 feet, that would have meant that it was dry low-land until the Great Melt. Since human settlements tend to favor coastal low-lands, it would be surprising if those oral traditions did not mention how they had to move to higher ground. Have you also surveyed the oral traditions of long-established high-land settlements?
Actual prehistoric floods are discussed in the Wikipedia article at
Outburst flood - Wikipedia -- sorry, the only other language it's in is Russian.
PS
I'll add a cautionary tale here about assuming too much about a people's oral tradition. I read this in a Science 80 article nearly 30 years ago, so bibliographic references are not available.
The article mentioned an isolated tribe in Afica with "no contact with the outside world". Their mythology involved the brighest star in the night sky, Sirius, AKA "Alpha Canis Majoris" ("Dog Star"). Ethnologists were astounded to find that that myth included a small companion star. We had only relatively recently discovered the presence of a white star orbitting Sirius, Sirius B, which is invisible to the naked eye and can only be seen by a large-enough telescope. It was a mystery how this primitive people could have known about the existence of that white star.
Until they researched back into earlier visits to that tribe and found that the myth as first recorded had made no mention whatsover to any companion to Sirius. That tribe was not so perfectly isolated as they had thought and when news of Sirius B had reached that tribe they immediately incorporated it into their mythology.
In my German studies (third and fourth year included literature classes), the Romantic era (which the French also had) was based nationalism and a fascination with the supernatural, the macabre, and folk history (yes, I know that's an oversimplification). The point is that one of the Romanticists' conceits was that folk stories were accurate records that went back countless generations. For example, the Brothers Grimm in the course of their linguistical research collected folk tales, which is what we know them from now (unless you were a linguistics major).
Well, that conceit was wrong. It turns out that those folk stories only go back a few generations at most.
Edited by dwise1, : PS