This comes to us via the epic of Gilgamesh[0], perhaps written around 2100 BCE.
Small extract:
“ Ea commanded Utnapishtim to demolish his house and build a boat, regardless of the cost, to keep living beings alive.
The boat must have equal dimensions with corresponding width and length and be covered over like Apsu boats.”
There is an excellent in our time episode which covers this epic, the Sumerian language and translation which I found one of the most interesting episodes they have made [1].