I've heard this claim made before, and it is so stupid. Assuming the creation is literally true (which I do), the former world was destroyed in the flood. The Euphrates and Tigris rivers that exist today are not the same rivers mentioned pre-flood. They are rivers that were named for those rivers. The Garden of Eden could have been in Nebraska or Japan. The former world was washed away. Noah was in the ark for a year, floating randomly. None of the previous landmarks would have survived the flood, although new landmarks would be named for the old ones.
Excellent point!