Mountain Rivers and Water Falls

All rivers in the game, as of right now, are seated at sea level.

My idea is to add smaller rivers that exists at the same hight as it spawns on. They would flow down from peeks and connect to the "normal rivers" or oceans. 

This could allow us to generat woulds with mountain rivers, water falls (when the terrains hight changes fast) and sweat water slides  :)

This could help spice up the empty mountains, and bee sick :P