Good questions.
Up to 15 cubits (22 ft / 6.5 m) of water overwhelmed them. (Genesis 7:20)
It was a global deluge.
22 feet of water? Where? That might be a problem if you live in the Maldives, but I'm 600 feet above sea level here.
Or do you mean it was 15 cubits above the highest point on Earth, so that low-lying countries would have been under five miles of brackish water?
The Bible uses the term "kinds" of animals, which differs from the biological term "species." The biological "kind" or "species" consists of any group of interfertile animals or plansts mutually possessing one or more distinctive characteristics. So there can be many such species of varieties within a single division of the Biblical "kinds."
The Biblical "kinds" are divisions of life forms in which each division allows for cross fertility within its limits. The boundry being, then, is the point where fertilization can no longer occur.
That's largely the same as species, so you'd still need an
enormous number of animals.
In other words the Ark didn't need to have every species of dog or cat.
Yeah, it did. It also needed every species of echidna and every species of platypus (okay, there's only one) and every species of wombat and every species of kangaroo and wallaby, and every species of possum, and the quoll and the quokka and the Tasmanian devil and the thylacine (sure, they're gone now, but they lived until the 1930s). And zebras and lemurs and langurs and llamas and giant tortoises and fanged frogs and giant rats and capybaras and alpacas and wildebeeste and okapi and, well, it's quite a list. I can think of several times more than 43 non-interfertile placental mammals just off the top of my head.
That isn't really a question, but a quick response . . . according to Bible chronology the flood took place in 2370 B.C.E. The Akkadian Epic of Gilgamesh, as we know it from the library of Ashurbanipal (who reigned from 668 - 627 B.C.E.) didn't begin to circulate, fragmentarily, until 1900 B.C.E. so how you came to assume the former was inspired by the later is beyond my comprehension as well as, I would like to think, the comprehension of science.
You seem confused.
You are claiming that one story that was written later than another story could not have borrowed from the earlier tale because elements
in the story were placed before the date of the oldest known copies of the earlier tale?
You seem to have included every possible logical fallacy in a single short paragraph. Well done!
The water came from a canopy of water vapor that surrounded the earth up until the flood.
Really? And what is your evidence for this canopy of water vapor, given that it is a complete physical impossiblity?
Where did the water go? Nowhere, the earth is about 70% water.
No it isn't. 70% of the Earth's
surface is
covered by water.
It is possible that the oceans were smaller and the mountains were lower.
In the last 5000 years? No, it's not possible. Mountain forming on anything like the scale you suggest within that timeframe would have involved sufficient tectonic activity to melt the Earth's crust and boil all the oceans.
River channels reach far out under the ocean.
Yes, they were carved out during the last Ice Age.
Which your Bible somehow neglects to mention.
There is ten times as much water by volume in the ocean as there is land above sea level.
Even if that is accurate, so what?
The polar ice caps have been around a whole lot longer than 5000 years.