I get there by a different path.
- Archeologists tell me the Bible is the most authenticated historical document in existence.
- I read the document and found the authors to be credible.
- Their accounts convinced me that Jesus was God in the flesh.
- Jesus says that the accounts in the Scripture are true including Noah and the others I mentioned. Q.E.D.
So, I don't need any other evidence. Given that Jesus demonstrated over and over again that He had complete mastery over the laws of physics, I believe that God can make something as big as a global flood happen without leaving a trace.
I do understand that if someone just tosses the story of Noah's ark in your lap without all that background, you might be a tad bit skeptical. :o)