Today I saw an Godot engine tutorial about creating waterfall shader. I made in PlayCanvas and decided to share it freely. (It also contains some model to make it better)
You can find more on Harry Alisavakis
And here is tutorial about shaders : http://halisavakis.com/my-take-on-shaders-unlit-waterfall-part-1/
Here is the project link in case you want to clone or use it :
Here is Youtube video :
You can change, colors and speed of waterfall with script.