Have you seen the documentary called "In Search of Noah's Ark"? I found it quite compelling, even including numerous eyewitnesses including (now) very old 'locals' who had climbed Ararat as kids and had even entered a very large wooden boat (with fathers, grandfathers, etc.). Anyway, I've always been convinced that the Ark is on Ararat and just curious why you don't believe it is.
Perhaps the following will enlighten you. From a book called "Before the Flood - The Biblical Flood as a Real Event and How it Changed the Course of Civilization" by Ian Wilson, 2001; which documents that yep, there really was a flood, and yep, there really was a civilization that got trashed, and yep, it really did happen in that area. So, yes, there is real scientific evidence for a major (and I mean HUGE) flood that happened within the general timeframe in question. However, as to why the Ark is not on Ararat there are a number of reasons. I will, however, just quote to you some of the problems.
Ian Plimer, Professor of Geology at Australia's Melborne University...took the trouble to visit the Akyayla site with Fasold in 1994. Like Fenner before him, Plimer found it impossible to repeat any of the various radar, seismic, magnetic, and electromagnetic tests claimed by Wyatt. During this expedition, apparently Fasold himself came to recognise that what Wyatt had argued to be 'boat ribs' wer no longer evident, concluding that these must have been deliberately scraped into the soil to appear as they did in Wyatt's photographs. According to Plimer's professional judgement the Akyayla boat is simply an outcrop of 120 million year old sea floor rocks (ophiolite), around which a more modern (and still moving) mud slide has flowed...In the light of Plimer's findings Fasold, having come to realise that Wyatt and Roberts had behaved deceptively, completely changed his allegiance. In partnership with Plimer he successfully sued Roberts in the Australian Federal Court. And as further related investigations revealed the self-styled 'biblical archaeologist' Ron Wyatt, who died recently, was in fact a Seventh Day Adventist nurse anaesthetist based in Nashville, Tennessee. As for the Florida 'university' quoted as the alma mater for 'Dr' Allen Roberts, this turned out to be a letterbox outside a fundamentalist church from which fake 'doctorates' can be obtained for just a few dollars.
Background on Wyatt and Roberts. Wyatt published "Discovered: Noah's Ark" in 1989, and Fasold published "The Ark of Noah" that same year. Roberts, along with Wyatt, founded an organization called "Ark Search" and they began publicizing that they had found the Ark. They produced a number of videos under the label "Amazing Truth Publications". In the end, they played fast and loose with the truth while making a bunch of money and getting a lot of publicity for themselves.
So, the reason why a lot of people are sceptical is that there have been a number of scam artists in the field happy to sell fundamentalist Christians what those same Christians wanted to hear -- and made a pile of money doing it, too. I suspect that some even on this board will not even read this far through this post and immediately post a bunch of ignorant responses about me and this information. Too bad. There is real scientific evidence for a serious and major flood in that region within roughly the time frame identified by the Bible. And if one considers that the Ark did not have to hold representatives of every animal in the world, but just the ones in that geographical region; and that a massive flood in that region would have wiped out a major component of the human race living at the time; from that perspective the Bible can be considered to be verified.
As for why it happened...as CS Lewis said about prayer (I paraphrase): "If you pray for something and you get no result, it shows prayer doesn't work. And if you pray for something and you do get result, why you can see the chain of cause and effect and you would have got the result anyway, right"? Heh heh. From my limited theological perspective, it is clear to me that God was protecting the human lineage that was going to lead to Christ. He took advantage of the climate and the geographical features to generate the major flood "burst through" and man, did it ever. And he wasn't shy of "trimming off" tribes and groups that could have otherwise threatened that lineage. After all, if He has "foreknowledge" he is going to see those threats coming. The flood (and other actions that people from a human perspective would consider brutal) make sense if he is protecting the bloodline that leads to Christ. And of course, again, this is IMO.
Anyone who wants a scientific historical perspective on the flood, I do recommend the above book. It is pretty well researched (has almost 50 pages of notes and references at the end.)