Sorry for the late reply. I've been busy with Christmas coming up. But, here's my best explanations for why I think those particular events actually happened.
Noah's Flood - I'm not sure what to believe as far as the flood goes in local or worldwide. I've always been taught that it was worldwide. But, not until recently have I actually looked into it myself. And, quite frankly, I'm questioning whether it is worldwide or not. So, I'll just give facts backing up both sides.
Worldwide Flood - We can look at it from a geological perspective. There's these things called Polystrate Fossils. These are fossils of trees buried right into the ground. These are found in several places in almost every continent (if not all). For instance, you can find some in Joggins, Nova Scotia. You can find them in random intervals throughout some 2,500 feet of layers of rock (called Strata). There were a few found that came out to be 40 foot tall trees. It'd be pretty tough to create some fossilized trees that tall without a quick burial that a torrent of water could bring.
Local wide Flood - You asked for justification through text. I'm going to give you proof through text in the Bible for now. I will update this when I can to give text outside the Bible. But, right now it's getting late.
Biblically disproving a worldwide flood - Alrighty, first off, I've seen some sites say that the verse Psalms 104:9 proves a worldwide flood is impossible. Though, I don't think that is a sufficient enough source to disprove something like the Flood. Psalms is a book of religious songs written by several different authors through a long period of time. No where in the Bible have I read that it says they were influenced by God that what they said was true. So, really, anything said in Psalms is subject to some man input. (Course, that can be said for a lot of the Bible, but let's keep things confined to the Flood :P).
Next, is just an argument of wording. There's these words in the OG Hebrew Bible. Kol (meaning 'the whole') and Erets (meaning 'Earth') is used a metric crapton in the book of Genesis. When they did use it, it could mean the people, or geographically, in several instances it means locally.
Then, when Noah and the crew get to the home stretch of the flood, it says "After forty days Noah opened the window he had made in the ark and sent out a raven, and it kept flying back and forth until the water had dried up from the earth" (Genesis 8:6-7). If you took that literally, we'd have no water on the face of this Earth. Now, with locale in mind, then yes, that makes sense.
Then there's something said in the New Testament where, in 2 Peter 3:5-6, "For when they maintain this, it escapes their notice that by the word of God the heavens existed long ago and the land was formed out of water and by water, through which the world at that time was destroyed, being flooded with water." He says "The world at that time" because not until God confused everybody by making different languages did the people spread across the world. The people of earth, at the time of the flood, were confined to the Mesopotamian area.
Finally, it'd make more sense for an ark to hold the animals that were in that specific area rather than the whole world's animals.
Ultimately, whatever you decide to believe, you have several facts to both prove and disprove the point in question. If only we had time machines......
Again, sorry for the late reply. Busy life is busy. But, I'll come back to update this with sources outside the Bible to try and prove a Flood and answer your other questions.