Upon close examination of the chapters of Genesis in the Revised Standard Version of The Bible, there are two versions of a flood story. These two versions are hard to separate as they are interwoven. It seems that there is one story and then a continuation of the origional story, not really two separate stories. In chapter 6 of Genesis a flood is foretold by Noah who talks with "God" and/or "the Lord" and then continues the account of what happened during the flood in chapters 7 through 9. The division of the story is shown through small details. In a third comparison another flood story is told in The Epic of Gilgamesh. This story accounts for a flood story told by the survior Utnapishtim and was written in a different area than the stories of The Bible.
To fully understand the story of the great flood and point out the details, I find it best to summarize most of the first chapters in Genesis. Chapter 6 of Genesis is broken down as follows; "The sons of God saw the daughters of men." (6:2) thus creating a population of humans who were very wicked and "the Lord was sorry that he had made man on earth". So the Lord tells Noah that he is going to destroy all the people of the earth except for righteous Noah and his family. It was even noted that Noah was so righteous that he "walked with God" (6:9). So the Lord tells Noah that he is going to flood the earth but makes a covenant with Noah that if he builds an ark, he will be saved. God gives exact building measurements of the ark in cubits. God also tells Noah to bring his family and extended family to the ark and also two of every kind of animal on the earth, male and female. God continues telling Noah to store every available food for himself, his family and the animals. Genesis, chapters 7-9 tell in more detail what happened during the great flood. The Lord tells Noah to brind seven pairs of clean animals, and one pair of other animals into the ark along with stores of food.