Question about waterfalls

[rasomaso]

Last time I watched the movie I noticed that halleluja mountains are full of waterfalls. Well I obviously noticed that before, but thinking about it, it appeared to me as odd for a floating cliff to have so much water. Where do you get all the water from? The rocks are relatively small compared to the amount of water in it's waterfalls. There are no underground springs and I doubt there is so much rain, when all the shots from the mountains actually show sunny weather.
Any thoughts?