If it is, I have a different system which I think looks better - A small tiled background (blue, with 50% transparency) stretched to the size of a waterfall. A canvas object is placed underneath it at the same size, grabs the cliff texture beneath it, and applies a bounded warp effect. It gives the illusion of the tiled background waterfall warping the cliff behind it. I'll then place some small simple textures on top of the waterfall to imply movement, inspired by this image.
So the main question is pretty much: Is the Plasma object more or less intensive than the Bounded Warp effect? I'm afraid I'm completely hopeless at discovering these answers myself
Many thanks for your time