This relates to the bible concept of firmament, flat earth and separation of waters, as in genesis when it says god separated waters above and below.
The nomads knew wells, rain, islands, tides and flooding rivers, so the world they conceptualised was one where God moved water above and below to reveal dry land. As such in the story it seemed logically consistent to allow massive amounts of water to come from above and below returning the world in what they considered a previous, erased state to reboot it.
This relates to the bible concept of firmament, flat earth and separation of waters, as in genesis when it says god separated waters above and below.
The nomads knew wells, rain, islands, tides and flooding rivers, so the world they conceptualised was one where God moved water above and below to reveal dry land. As such in the story it seemed logically consistent to allow massive amounts of water to come from above and below returning the world in what they considered a previous, erased state to reboot it.