Springs.
And what drainages would those have been?
See above.
The Bible does not say there weren't streams and/or rivers, in fact quite the opposite:
Genesis 2:5-6 "...and no plant of the field had yet sprung up, for the LORD God had not sent rain on the earth and there was no man to work the ground, 6 but streams [or mist] came up from the earth and watered the whole surface of the ground..."
I too used to accept the "...the straight scientific view...", but I have learned that that is academic elitist snobbery. From gun control to global warming to evolution, I find many holes in the theories (sometimes lies) that are foisted off on us as fact. I believe the Bible is God's inerrant word and that the explanations for our scientific observations can square with it. It usually takes someone far brighter than myself to do it but nevertheless...
If you choose not to believe, that is your business. I'm okay with that. Just don't dismiss it out of hand, keep an open mind while you are questioning and you may come around too. And as you said this is all just idle speculation.
>> And so... ummm... where'd the rivers come from?
>Springs.
And where'd the water for the springs come from? The evaporation/rain/snow cycle is the only means to get water uphill. Without getting water uphill, your spring would run dry, and that would be the end of it.
> I have learned that that is academic elitist snobbery. From gun control to global warming to evolution...
... and relativity, and chemistry, and biology and geology, and gravity....
> Just don't dismiss it out of hand
I dismiss nothign out of hand. Many things, though, as so astonishingly silly that the amount of evidence required to refute them is quite small.