It isn't atall clear to me that God did any such thing. If we're to take everything in Genesis as the objectiive truth, we end up with a very strange world indeed. Most cultures have deluge stories, and they all may well be true, at least from the viewpoints of those direcly affected. Did the entire world flood at once? Maybe, maybe not. Personally, I don't really care all that much.
My faith isn't based on Genesis. or much of the Old Testament, being literally true. God Himself intervened in human history to give us the ultimate Truth. To me the OT is of purely academic interest; Jesus Christ, God Incarnate, the Creator of the Universe, came to set things to rights. Our goal is to accept anf follow what He said, and not what we've decoded the OT "means".
I have also noted that a lot of arrant rubbish has been produced by Christians with what I consider an unhealthy revereence for the Old Testament. They cook up stuff like a literal (24 hour) day creation, even though both Old and New Testaments note that God isn't bound by time as we are. Many would require that all Christians be bound by the traditions of the ancient Hebrews, although our ancestors (certainly mine, anyway) were explicitly omitted from those commandments. They come up with purely nonsensical balderdash like the Flat Earth Rube Goldberg universe that would prove that God wasn't even a particularly good engineer. In addition, many, if not most, of the historical heresies that have plagued the Church have come from people who based them on egregious misunderstandings of the OT, and raising it to the equaling or surpassing in importance the revelations of our Lord Christ Himself.
Bother "liberal theologians". That jgenerally means "a theologian with whom I disagree". I am a Christian, not a Jew. My faith derives solely from the New Testament, the Testament of Jesus Christ. Where the OT supports the beliefs of the Church, then I agree with it. When if does not, or when it is in fact observably wrong, then I pay it no heed.