... he actually asked for waterfalls in mb3d
You made that video in MB3D??!!?
Impressive.
...
But yeah, like cKleinhuis said - just look at the 3D Software that does fluid simulations and how complex it is. Then find a good one, and look at the huge teams of people who work on it. Then look at the price tag!! A good example is the Tsunami plug-in for After Effects. It's thousands of dollars and makes great water surfaces with the ability to create cinematic huge waves. But even that fails at waterfalls. You'd need to trick it by rotating planes and adding spray at the bottom, etc, to make a convincing waterfall.
Very nice idea, but impractical to implement with a huge team - and I would venture to guess impossible for a single programmer to do well.