Not that I'm defending flood stories, but there are some interesting theories regarding glacial floods at the end of the last ice age being the Bibles source. Most likely these happened in many places over differing periods of time forming the global aspects.
http://discovermagazine.com/2012/jul-aug...y-enormous
Quote: Recognition of the Missoula flood helped other geologists identify similar landforms in Asia, Europe, Alaska, and the American Midwest, as well as on Mars. There is now compelling evidence for many gigantic ancient floods where glacial ice dams failed time and again: At the end of the last glaciation, some 10,000 years ago, giant ice-dammed lakes in Eurasia and North America repeatedly produced huge floods
http://discovermagazine.com/2012/jul-aug...y-enormous