Was the Old Testament plagiarized?

The Babylonians had their own story, one quite similar to the story of Noah and the flood in the Old Testament Christian Bible and the Torah.  A god came to one man, warned him of a impending, worldwide flood, and advised him to build an ark. The man was saved due to his moral constitution, and his story serves as a warning to all others.

Moreover, the Babylonians seem to have acquired their story from the Sumerians, one of the first urban civilizations who existed earlier than 2,000 B.C.  I think the Old Testament was written well after 1,000 B.C.

I'm not implying anything.  I just think it interesting.

Source: Kenneth W. Harl.  World of Byzantium.  Lecture 4: Hammurabi's Babylon.  2001.  The Teaching Company.