Oh but there IS evidence.No, we know that there was no flood since there is no evidence of one.
Five miles of water flooding and leaving the Earth would leave unmistakable evidence almost every where. There is no evidence of a flood, therefore no flood.
"Let's Look at the Evidence:
The following are 18 Evidences of either massive flooding and erosion, extremely rapid layering of strata, or direct evidence of a Worldwide Flood. Such evidences are found in numerous places on virtually every Continent."
You won't like it, you'll probably not even read it. But there is evidence regardless of your opinions.