In the first place, skeptical geologists propose that for such a flood to have occurred, we would find a similar stratum throughout the world covered with pebbles, sludge, boulders, and other elements. It is curious that this layer cannot be found, even more so when the flood narrated by the Bible had taken place in a time as recent as 3000 B.C.
Neither can be found the strata of fossils, with different animal and vegetable species occupying specific soil layers. According to flood logic, the animal remains of all species before the big flood
(including the extinct dinosaurs) should be found today in only one stratum, without any distinction. But paleontology completely contradicts these suppositions.
Yet these examples appear to be only the tip of the iceberg comprising the arguments that refute a global flood. Even so, much of such reasoning is refuted with equal grace by the “pro-flood” scientists.
The article actually gives a fairly balanced view on the issue. I think it's fascinating that so many cultures have some kind of a flood myth. Something must have happened to create that kind of cultural memory. But is that proof that the Bible's version is exactly what happened? Not exactly. Even so, faith requires believing something that can't necessarily be proven empirically anyway.
With respect to non-Biblical myths about a purifying flood, these can be found in the Hindu, Sumerian, Greek, Acadia, Chinese, Mapuche, Mayan, Aztec, and Pascuanese (Easter Island) cultures, among others. Several of these stories appear to possess surprisingly similar common
factors. Among the most repeated themes are those of celestial announcements ignored by the people, the great flood itself, the construction of an arc to preserve life from the flood, and the later restoration of life on the planet.
A clear example of this similarity is provided by pre-Biblical Mesopotamian history of the flood in which the god “Ea” warned Uta-na-pistim, king of Shuruppak, about the punishment that awaits humanity for its serious moral degeneration. Uta-na-pistim received instructions from the god to construct a craft in the form of a cube with eight floors, and said that it should include in it a pair of each species of animal, plant seeds, as well as his own family. Thus, Uta-na-pistim survived the several-day-long deluge, released a bird to verify the proximity of dry land, and made an animal sacrifice to the gods.
(Via the Agade mailing list)