When I was young I took all the numbers in genesis as unquestionable facts but then I learned that the Septuagint uses completely different numbers. (and there are other versions too)
I now see the numbers more as hints pointing us in the right general direction but not to be taken too literally. Having studied it I have concluded that the flood of Noah was probably the same as the flood of Atlantis which was also the same as the flood of Ogyges (Gog?) According to plato the war of atlantis was 9000 years before the time of Solon. Ancient Greek flood myths - Religion-wiki
The Ogygian flood is so called because it occurred in the time of Ogyges, a mythical king of Attica. The name "Ogyges" and "Ogygian" is synonymous with "primeval", "primal" and "earliest dawn". Others say he was the founder and king of Thebes. In many traditions the Ogygian flood is said to have covered the whole world and was so devastating that Attica remained without kings until the reign of Cecrops.
Plato in his Laws, Book III, argues that this flood had occurred ten thousand years before his time, as opposed to only "one or two thousand years that have elapsed" since the discovery of music, and other inventions. Also in Timaeus (22) and in Critias (111-112) he describes the "great deluge of all" as having been preceded by 9,000 years of history before the time of his contemporary Solon, during the 10th millennium BCE. In addition, the texts report that "many great deluges have taken place during the nine thousand years" since Athens and Atlantis were preeminent.
The theory of the flood in the Aegean Basin proposes that a great flood occurred at the end of the Late Pleistocene or beginning of the Holocene. The Holocene is a geological period that began approximately 11,550 calendar years BP (or about 9600 BCE) and continues to the present. This flood would coincide with the end of the last ice age, estimated at approximately 10,000 years ago, when the sea level rose as much as 130 metres, particularly during Meltwater pulse 1A when sea level rose by about 25 metres in some parts of the northern hemisphere over a period of less than 500 years
Read more: http://www.city-data.com/forum/religion-philosophy/1536830-flood-noah-10-000-bc-egyptian.html#ixzz1uaFMHfAM