Does science know all there is to know?
There are plenty that science know about the earth, including ancient climate and natural disasters, but there are of course, some that cannot yet be explained.
But what it doesn't explain, doesn't mean that we can attribute these event to any divine or supernatural phenomena or event (eg Flood).
What if the land areas were much lower pre-flood to what they are now?
Here, you are making assumptions, but you have not presented any evidence to support your speculative question.
You cannot even produce WHEN this alleged Genesis Flood occur.
What date did you think Noah and the Flood happen?
Unless you know that, you cannot possibly compare the Flood to any geological and archaeological evidence.
And if there were such flood that happened globally, there would be signs of such flood, in the soil, on the rocks, on the tree rings, and on any archaeological sites that may have survive the flood, like buildings, not just in one location or region, but everywhere, around the world, since you are claiming it to be a "global" flood.
A flood that lasted nearly a year, should leave so many signs, dating to the same time. But there have been no such evidences.
If you think the lands, including the mountains were "much lower" as you claim, then you must show empirical evidences that all land areas were indeed "much lower", and that it occurred at this date that you proposed for the Deluge.
There are many evidences, that no global flood occurring during the history of man, during the last 5000 years or even the last 10,000 years.
According to Genesis 8, the ark rested on top of one of mountains of Ararat. Today, the highest peak (Greater Ararat) is 5137 metres high.
Evidences showed that there have only being 2 major volcanic eruptions in antiquity (meaning during the Bronze Age and Iron Age). One in the Bronze Age, occurring some time between 2500 and 2400 BCE, another about 550 BCE, Iron Age. Since this last one, there have only 3 minor volcanic activities.
None of these activities or eruptions showed that volcano of Greater Ararat changed its elevation significantly to warrant your speculative "much lower" lands, as you are claiming. Most of the rise of the mountains of Ararat, occurred millions of years before the appearances of the Homo sapiens.
Much of the mountains at Ararat and around it, started in Middle to Late Eocene epoch, and then Miocene epoch, and even the Pliocene epoch, where the region was more active. No humans were around this time.
The biggest volcanic activity when humans were around, occurred around 2500-2400 BCE, where it destroyed one Bronze Age settlement, of Kura-Araxes culture.
This Kura-Araxes actually started in Armenian plateau, about 3400 BCE, as Neolithic culture, producing specifically designed pottery. The Kura-Araxes culture spread as far north as Caucasus, which continued to exist till 2000 BCE.
If my calculation his right, that using any modern translation of Old Testament bible, based on the Masoretic source, then the Flood would have occurred around 2340 BCE.
Now, i am right about when Flood possibly happened, then the entire region of Armenian Plateau should be covered under water, killling everyone there. The people of Kura-Araxes culture should have died out, and SHOULD NOT BE producing the same style of pottery.
The archaeological evidences that this Kura-Araxes pottery remain the style of that entire region, unchanged, then the Flood could not have happened.
If there were pre-Flood and post-Flood cultures, existing in that region, you would expect one culture would end, and new culture would begin, with a new type or style of pottery. But that's not the case, in the region, near the mountains of Ararat.
The very fact that culture exist throughout much of the 3rd millennium BCE, demonstrated that no such Flood occur.
It is the same with 3rd millennium BCE Mesopotamian civilisation in the southeast, Egyptian civilisation in the southwest, or the palace-building of Minoan Crete in the west. No interruptions to these cultures, only prove that such a Flood never happened.