outhouse
Atheistically
I think if the river flooded the land as far as the eye could see they would see that as a supernatural event, which they would pass on orally. It is just a thought. But if you go everywhere on foot, you might not know that it was just your area.
well that is exactly what happened
the valley the Euphrates flooded was very flat and the flood of 2900BCE left 3 flood stories from the sumerian culture.
The same semetic people would have migrated from when the sumerian civilization collapsed, bringing these legends with them. Its also why much of noahs flood is word for word straight from the previous versions.
You have to remember, ancient hebrews were a new people with no real history of themselves, they had to create their religion as fast as the their new cultures population exploded which was in a few hundred years and that is exactly what we see.
Created history using influences from the only history these semeitc speaking people had, others claiming it as their own. with that said they did add their flare and flavor to the previous legends