Legendary u -
At last someone has revealed the truth! No, nothing in the Bible is symbolic; everything is literally true. Which means that the new heavens and new earth can only come when those now existing are burned away by fire. Which means we're all screwed.
Seriously, the question "is Genesis true?" would have made little sense to Jesus of Nazareth. His saying 'just as in the days of Noah' no more makes the Noah account accurate than my saying 'like the boy who cried "wolf!"' means that the fable referenced actually took place. We don't usually think of a fable as a lie - even though it is not factually true - we think of it as a story with a point to make.
In the ancient world such stories were highly valued because they taught important lessons. They were the "mythos," while true stories - which told what really happened, but gave little insight into why - were "logos." Today, apart from children's stories, we rarely grasp that mythos can be important without being "true."
Far from being bereft of symbolism, the Bible is almost entirely symbolism. There is a deeper meaning to each of the stories, and the perceived validity of that meaning has nothing to do with whether the events of the story actually took place. Similar events surely did, but without the clear meaning imposed by the integration of gods and their dealings, the meaning was not as clear.
Today we look for meaning not by examing the minds of the gods, but those of men. We find better answers on whole. We know that sometimes a cigar is just a cigar, while some of our forefathers could not imagine that lightning can strike without sending a message.
The story of a brave old man trying to rescue his livestock from rising floodwaters is worthy of Hemingway. Making such into a story about a Creator who breaks his own physical laws with global flooding and water canopies adds nothing to the value of the mythos.