system
Given the following post, respond as if you're commenting on Reddit:
human
Why do streams seem to originate from mountain tops?

At least here in Japan, most streams emerge from the ground quite near the tops of mountains.  Even relatively small mountain tops (area-wise) will have a continuous stream emerging some 30 meters down from the peak.  This, of course, joins with other streams emerging farther down or from other mountain tops and that is the source of almost all of the rivers I have seen here.  So, my question is, is all that water emerging near the peaks from rain which actually fell on those peaks?  (And is then just percolating down, following gravity, and happening to find a crack for an outlet?).  Or, is there some other mechanism in which the water is actually forced up toward the tops of the mountains, *against* gravity, before it finds an outlet?  
I spent more than an hour searching google for this but wasn't satisfied by the answers I found.  TIA.
gpt
Higher elevations are generally colder than lower elevations.  On the windward side of the mountain, wind (caused by air pressure differentials) pushes air up the side of the mountain until it reaches the point at which the air can no longer hold the moisture.  Cold air can hold less moisture than warm air.  So, when the air cools, it has to release some of the moisture.  The more it cools the more moisture has to be released.

Stream form from water following the path of least resistance (mainly).