what is logical

at the waterfalls today, my mind wondered from the sight of these powerful gushes of water falling perfectly in seemingly predetermined angles to provide maximum effect. i had a few questions.

1. where does all the water come from?surely it cant be rain.
2. if it did come from rain, it would require it to rain all day everyday in order to keep enough water flowing that way. but it doesn't rain that often. so could that be it?
   
3. if so, when it doesn't rain, does the waterfall stop having water falling from it?
4. if suppose its a continuous cycle of water like those fountains for your garden that have pumps to get the water back up, that would mean the water coming from the falls that flows into the river would have to flow back upstream and up the falls again. wouldnt that be illogical for water to defy gravity?
5. how do i Google such information? -the science of waterfalls?

"We spent some time together crying. Spent some time just trying to let each other go. I held your hand so very tightly and told you what I would be dreaming of. There's nothing like you and I, So why do I even try?"- nothing like you and I, the perishers