[Attrecomet]

> It seems that most early civilizations that developed on alluvial flood plains...

I'd go even further: there is no human habitat at all where floods are not dangerous catastrophes. The coast and alluvial plains trivially so, but mountains and deserts, too.

[seanhunter]

I might be misunderstanding your point, but Egyptian civilisation was entirely based on the flooding of the Nile bringing fertility to the farmlands. It wasn't a dangerous catastrophe, it was a benevolent event that was celebrated with religious feasts etc dedicated to Isis iirc (long time since I read my Egyptian mythology).

[Attrecomet]

My point wasn't that each flood has always been detrimental, but that there has never been a collection of people living in a place where there aren't also dangerous floods that kill people, so wild stories of floods destroying the world aren't really far out for the lived experience (perhaps across a few generations) of any human ever.

Edited for clarity

[seanhunter]

Got it. Yes indeed. That makes total sense and I agree.

Also at some point in prehistory the rock formation that is now the strait of Gibraltar fractured and the Atlantic ocean rushed in and drowned the entire basin of the Mediterranean,[1] so that type of cataclysm has actually occurred, although before human experience

[1.] https://www.theguardian.com/science/2009/dec/09/mediterranea...