Well, mister zone, let me explain the timeline to you, since you seem to know it all.
First of all, the Bible is a recurring prophecy. The events described in it come to pass at the end of every Age or "Yuga", in the Vedic timeline. We are swiftly approaching the end of the fourth Age or "Kali Yuga".
What you need to understand is that these Ages are all of finite length. They are based on the "procession of the equinox". We are currently coming to the end of the fourth Age. There are specific events that occur at the end of every Age, that must happen.
There is a "prophet for the end of the Age" named in each.
There is also a battle that is officially titled, "The battle of good and evil that must be fought to end the Age". The battle for this current Age is the biblical "battle of the Armageddon". The first three battles, were respectively, the battle that is recalled in the "Epic of Gilgamesh" for the first Age, the "battle of the Ten Kings" where Moses kicked the Egyptians butts for the second Age, and the battle that must be fought in the third Age, was the Battle recounted in the Mahabharata.
There is a cataclysmic event that occurs at the end of every Age as well, and the flood of Noah was the event that ended the third Age.
The event that ended the second Age, which was the Age of Moses, was called the "Deluge" or "flood of Manu".
The "procession of the equinox", which these ages are all based upon, is 25,700 years in length. This Age is one procession in length. The age of Noah was two processions in length, at roughly 52,000 years. The Age of Moses, which was the second Age, was four processions in length at 104,000 years. And the first Age, of Abraham, was eight processions in length, which I'll let you figure out since youre a math genius.
So, absolutely, the flood did happen, twice. But the flood of Noah only once.
You're basing your assumption on a mathematical formula that isnt wrong in terms of the amount of rain possible, but assume that every one died in the flood. They did not. Looking at the time line of ireland, it becomes clear that they survived the flood, but then forty days and nights of rain is just the usual weather there. Go back to the Fomorian culture, who showed up there after the second flood or Deluge, and you'll find that the place was deserted, but there was evidence of life that they found there. That is because the people that lived there previously did not survive the Deluge, which was caused by a comet impacting in the laptev sea. The scar left in the earth from that one is still visible on satellite images. So, the flood of Noah really didn't effect Ireland because of the height of the island.
What you also fail to understand is the Bible is nothing but a eschatological prophecy, period, from beginning to end. There is no message of "good hope" in there. That was shoehorned in to it be the council of Nicea where the Bible was framed from ancient Sumerian and Babylonian texts.
And, another thing, mister geology, is that modern science does not understand the speed at which carbon degrades, and the timeline that you think you comprehend, is completely skewed.
When you consider the notion the modern science place the battle to end the first Age at a mere 20,000 years ago, and the actual timeline, places it more than 175,000 years age. That's a serious discrepancy.
So, the flood of Noah did occur, but you shouldn't worry about that. What you need to concern yourself with, is where you're going to be when the cataclysmic that ends this Age happens.
There is a thirty mile wide comet that will impact the earth in equatorial Amazonia that you probably want to get good seats for, since you'll be here for that one.
trust me, you really don't want to go there 
