You know what's really silly? It's when people who are hostile to the idea of the Flood try to imagine what it would have been like -- or even think they understand what Flood believers say about how it happened. THOSE ideas are sheer silliness.
Faith on several occasions has asserted that no one can know what the Biblical Flood would have been like.
That seems to be a really silly assertion once again totally refuted by all the evidence, reason and reality; so I think it might be worthwhile to explore both why it is possible and what the evidence of such an event MUST be.
First, the two stories give us beginning criteria; rain for 40 days and 40 nights.
Water from the rainfall and from unspecified "fountains of the deep".
All the water recedes over about 12 months until fertile land is again exposed.
So based on those assertions from the stories and considering reality, physics and geography we can make a few basic conclusions.
The water that fell as rain had to come from water already in the seas so there would be a net rise of water level from rain of zero.
The water from the "fountain of the deep" would result in two effects; local land subsidence at the source of the fountains extending across the area above that aquifer; and local flooding around the fountains.
Water taken from aquifers would have a long recharge time and so the water from the "fountains of the deep" would remain as surface water for longer than the time between the supposed flood and today.
The land that subsided over the source aquifers would still be at the level of the initial subsidence and most likely show up today as lakes immediately over aquifers and that that did not exist over 4000-4500 years ago.
While loose materials would be washed down hill to be deposited at lower levels there would be almost no additional noticeable wear to any lithified rocks. The floods total duration is simply too short to cause any appreciable erosion to anything but loose materials and extremely soft surfaces.
What would get deposited during the recessional event would be a jumbled mass of mostly unsorted materials with the only identifiable sorting being most dense items on the bottom graded to least dense items at the top.
There should be a uniform and universal interruption of existing cultures, biology, environment and ecology that shows a radiating pattern of return beginning somewhere near where the Ark of the stories was supposed to have ended up.
What the above are based on?
We can look at the current real evidence found in the world today to make conclusions based on current processes as well as geology, physics, chemistry, hydraulics, current annual events like monsoons and major annual flooding and land subsidence as we pump waters out of aquifers and wear to lithified materials seen in falls and from rainfall.
Those processes; getting water into the air to fall as rain, measuring erosion to lithified surfaces as found all over the world, measuring subsidence, measuring aquifer refill data, looking at the result of floods and tsunamis and annual inundations give us baseline studies that can then be used to make predictions given the conditions laid out in the stories.
Are there other things based on reality, physics, chemistry, geology and paleontology that should be seen?
Are there other things that must be seen if the Biblical Flood really happened?