What Asimov himself directly said in his Noah's Ark thingee (
from Asimov's Bible book) is----
This, according to the Bible, was a world-wide deluge, but there is no record of any such phenomenon, of course. The Egyptian civilization, for instance, was in a particularly flourishing state at this very time and was building its pyramids. Nor do the Egyptian records speak of any floods other than the annual overflow of the Nile, as far as we know. This is not to say, however, that the Biblical story of the Flood was not based on some actual, but local, flood in Sumerian history."