Sorry, you can't just change the bible to mean anything you want. It talks about a worldwide flood, not a regional flood, and no amount of calling the bible bs, as you do, will change that fact.
Plus, where's the proof of such a, even regional, 40 day flood that covered the whole area/earth?
We can understand a story the way the author meant it to be understood. When the story was written, no one was aware of the size and shape of the planet. What they did know is that as far as the eye could see, their world was covered in water. Science and details from scripture are helping people today pinpoint exactly where this great flood was--and what caused it.
Also worth remembering is how "forty days" is used throughout the Bible. It appears to be a figure of speech where the exact time is not the issue. The point is that there was a time of trial and testing--sometimes measured in days, sometimes in years. (There were days of trial and testing; there were years of trial and testing.)