What you are asking about is called euhemerism. Its name comes from the Ancient Greek philosopher called Euhemerus who believed that the gods and myths of Greece could be interpreted as natural phenomenon that had been enhanced in the telling of their stories. So Zeus, in his view, was an actual king of Crete in the distant past and he was made into a god by his people over time.

Today, that sort of interpretation is not favored by mythologists or serious historians. Critical theory has undermined the foundation of inventing an entire supposed "true" background for the mythologies of the past. It's not up to us to make up what was "really true" about the stories that we have. We have to confront the stories as written and interpret them in their own contexts. We can learn a lot from them, in that way.

For instance, we've learned a lot about the social milieu of Early Medieval Europe by analyzing Saint's Lives: what the economy was like, what social roles were, etc. That doesn't mean we can declare with confidence that, for example, when St. Benedict broke a glass full of poison by making the sign of the cross over it, someone actually threw a rock at it. Or the glass was just faulty. Or he bumped it under the table. Or any other invented explanation.

The same goes for all the invented explanations for events like Noah's Flood. It's a story about faith, evil, punishment, and redemption. It's not a scientific account of a flood, and we don't need to invent such an account. It's no surprise that people, who generally live near rivers and flood plains, can invent flood stories. We can't reconstruct what "really" happened. We have to take the tale on its own terms.

You'd probably find /r/academicbiblical useful and interesting. Check their wiki out.