I have used a card object with three displacement maps, one for the horizontal rounding, and one for the lateral rounding so that the card gets a bend. On top of that, there is a displacement for the water structure. And of course a transparency map.
The problem is that I constantly have to go back and forth between Photoshop and Terragen and that the smallest differences in gray value have major consequences.
What I don't manage to achieve is the softness of the edges of the waterfall because the transparency has only two values, transparent or not, so no soft transition. I have tried to solve this by building up a grid of very small dots in the transition.
It is therefore basically a proof of concept