The Worldwide Flood
There are lots of comments about how much water it would take to inundate the whole world with a flood, and where the water would go after the flood.

There is currently enough water to cover the entire surface of a flat earth with about a mile and a half deep of water. Prior to the Flood, a great deal of this water was under the earth as the Bible says in Genesis 7:11—-“. . . and the fountains of the deep opened up.” (Recent reports suggest that there may still be more water in the crust than there is on the surface.) And the world was much flatter than it is today, perhaps just one continent. So there was plenty of water to flood the entire land surface of the relatively flat earth.

There were tremendous tectonic and volcanic activities during the flood. As a result, the continents rose and the ocean floors sunk, just as the Bible records—Psalm 104:8. As this occurred, there was rapid water runoff from the continents into the oceans. During this time is when much of the water laid down sediments and fossils were created, as well as the continental shelves. All agree that on the highest mountain in the world, Mt. Everest, that there are marine fossils, and that these mountains were raised by tectonic activity. What young earth v. deep time advocates disagree on is how long this lifting process took, not that this is what happened.

Overall, the geological evidence we see today is best explained by a worldwide catastrophic flood.