Man has always lived near water. The "whole earth" in that context meant the inhabited part; we are now living on areas which were viewed as plateaus prior to the flood and were sparsely if at all inhabited. The waters of the flood have not gone anywhere; there was simply not as much water on the Earth before the flood as there is now. As to salt, that apparently came with the flood. There is no reasonable theory as to a source of the salt in the oceans, on this planet at least.
How do you decide what parts of scripture to ignore, and what parts to interpret re-write so that you can shoe-horn it into a fit for your theories?
I'm sorry, I made the assumption that you were a mainstream Genesis-is-literal-truth creationist. Are you not? Have you received some kind of personal revelation from God? Aliens? Um... Art Bell?
It is written... Gen 7:19 - "And the waters prevailed exceedingly upon the earth; and all the high hills, that were under the whole heaven, were covered." Gen 7:23 - "And every living substance was destroyed which was upon the face of the ground..." Sounds like a lot more than a little coastal flooding to me. Looks like everything's wiped out right up to the tree-line (about what? 11,000 feet above sea level?). Another big problem for mainstream creationists: after 150 days to 1 year underwater (Gen 7:24-8:13), pretty much every form of surface plant life has been killed off, but only fauna was herded on board the ark. So how come we still have a couple thousand species of plants on land? Heaven knows, they couldn't have evolved from waterplants....
The waters of the flood have not gone anywhere; there was simply not as much water on the Earth before the flood as there is now.
The ark settled on the mountains of Arrarat (Gen 8:4) and the waters "decresed continually" (Gen 8:5). And "the waters were dried from off the face of the earth" (Gen 8:13).
As to salt, that apparently came with the flood. There is no reasonable theory as to a source of the salt in the oceans, on this planet at least.
So what are you proposing? A "reasonable" theory that during the flood it rained saltwater, even though that flies in the face of science and isn't mentioned by scripture? You realize what that means, don't you? Noah had to stock a 1 year supply of fresh water for his family and all the animals. Like Roy Scheider said in Jaws: "We're gonna need a bigger boat."