If you have questions about the flood you can probably find most of the answers here:
http://www.answersingenesis.org/articles/am/v2/n2
http://www.answersingenesis.org/articles/am/v2/n2
His invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse.
Romans 1:20 ESV
Romans 1:20 ESV