It depends a lot on where the farm is, how much they irrigate, and when they irrigate. But often something like >90% of the water goes back into the ground, where it will eventually make its way back into the aquifers and rivers.
It's why often farm water usage is not nearly as bad as it superficially seems, and why farm water usage of a river can be multiples of the actual river flow
It's why often farm water usage is not nearly as bad as it superficially seems, and why farm water usage of a river can be multiples of the actual river flow