How could mountains be created by flood waters receding? Receding from what point? How does that push up land into mountains almost 30,000 feet high?
But regardless, there were mountains of some kind. Be they 5,000 feet high or 10,000 feet high that's still thousands of feet of water that had to come somewhere. Where did it come from and where did it go to?
And what about fresh water and salt water? The Earth's waters are 97% salt. Undrinkable. Catastrophic to farm land. If the flood covered the entire globe to a depth of hundreds or thousands or tens of thousands of feet then that means the tiny proportion of fresh water was basically swallowed up in a sea of saltwater. So without any fresh water again what did Noah drink? Without any land uncontaminated by saline how did anything grow?