This is absolutely true. Look up the rocks conditions. The erosion and oxydation patterns, the way they are dispelled on the ground. All identical.
No doubt those flooding events killed lots of people, and left an impression in stories, and legends. Civilisation came later though.
The only flooding that happened very suddenly on large, but still not global scales, was the flooding due to the melting of glaciers at the end of the ice age.
Metling of glaciers don't utterly destroy huge blocks constructions.
It does when much of that melt is the size of a large lake, small sea, and suddenly bursts from an ice wall dam. That happened a lot around the ice sheets.
