There are no eye-witnesses of the flood. All others cannot prove or disprove too much, as their is not really conclusive evidence against or for either case, just indications at best. Why all these discussions? Limiting your imagination to what humans can achieve today or a non-eyewitness report of the event 1000 years later, cannot be sufficient to provide us an all details covering explanation. Just remember, it is not the purpose of the bible. And whatever others have said about the use of the word 'earth' and 'world' in hebrew in Greek is also true.
If you would have unlimited resources at your disposal, and would have concluded to remove every living being on the planet by water, why should you limit yourself to using only rain? Why not using some extra gravity to make water raise and drop (let the moon come near, or another satelite or comet)? Or use some extreme wind force to push up levels? Or using some magnetic distortion with the same effect? Or a combination of all of it? The options are unlimited, really. Any of these means would:
- leave almost no traces, after more then 4000 years
- achieve the goal of killing all humans
- having the mountains covered in one area while in other areas the ocean is nearly empty is not a problem
- Solve the problem of sufficient water volume, the volume in the oceans is enough as supply
- still leave the possibilty of letting the flooding in the Iraq-Turkey area last longer then anywhere else, making it possible the arch ended up on the Ararat.
If you can believe God created the universe, creating a flood of moving waters all over the globe is actually nothing really major to do. Just imagine yourself with enormous (divine) power with a set challenge to make the flood happen. Would you limit yourself to just using rain? I don't think so... I think the only debatable point is the moment of the event, but that is another topic.
Did I prove the global flood? No. I only made it a possibility. If you want to believe in God and the bible, then try to think about his possibilities, even magic is in reach. If you want to discredit the bible and God, you will find the means to do so. Either way, your motivation is your drive and cause, and it will define your arguments. Who is correct? We will only find out later on.