I've been trying to figure out how to introduce this one because it's not quite the same as paraphrasing something from the Bible. The other problem is the fact it really is so similar to the story of Noah's flood that I swear at times I was reading the same thing with different names. So the best to start I think is to give you all a link to the flood story from the Epic of Gilgamesh: The Great Flood: Gilgamesh (I really suggest reading it because you'll probably be a tad lost later if you don't)
One thing I want to note is that the flood story from this epic is not about Gilgamesh himself, rather it is told to Gilgamesh by the flood survivor named Utnapishtim (I've actually seen TV documentaries get that bit wrong), who is the story's version of Noah. Utnapishtim even builds an equivalent to the Ark which he takes animals on as well (it's not as apparent while reading it, but that is the case), although it is a giant cube apparently with all sides being the same.
Besides the name there are a couple other key differences to this story. For instance there are multiple gods, in particular the Anunnaki whom you should all know from my adventures into the works of Zecharia Sitchin. In fact it is the Anunnaki named Enlil who apparently rashly decides to destroy humanity with a large flood because they have angered him and many of the other Anunnaki.
The other primary difference is that the flooding process itself lasts only 7 days and 6 nights as opposed to the 40 days of Noah's flood. There is also a really cool description process here telling about gods drawing back gates and releasing water, burning the human settlement, and much more. It's almost like reading about a Viking or pirate raid, only the Vikings and pirates are replaced by gods.
Anyways over the coming days I will get more into detail about these differences, as well the similarities, between this and Noah's flood. Like I said, I swear I was reading the same story at times...truly fascinating.