I made a fact checking
If the people of the old, know about "vapor"
Up to the time of the Renaissance, it was thought that precipitation alone was insufficient to feed rivers, for a complete water cycle, and that underground water pushing upwards from the oceans were the main contributors to river water.
Bartholomew of England held this view (1240 CE), as did Leonardo da Vinci (1500 CE) and
Athanasius Kircher (1644 CE).
The first published thinker to assert that rainfall alone was sufficient for the maintenance of rivers was
Bernard Palissy (1580 CE), who is often credited as the "discoverer" of the modern theory of the water cycle. Palissy's theories were not tested scientifically until 1674, in a study commonly attributed to
Pierre Perrault. Even then, these beliefs were not accepted in mainstream science until the early nineteenth century.
Water cycle - Wikipedia
I guess they only knew of it in 1580 CE,
The Book of Genesis was written 1450 BC to 1400 BC.