Mind blowing-waterfall illusion, seemingly defies gravity

This video is amazing. I've watched it a half-dozen times, yet I still can't quite fathom how this works. The water does "appear" to be moving up the slope, but upon closer inspection, especially given the perspective you see it from, it also looks like the water is running across the floor at a parallel or slightly downward slope.

The part I can't figure out, is where the water goes once it reaches the end of the "track". It's possible that the "top" of the waterfall is a separate piece, placed in the foreground in such a way, as to appear to be connected to the slope on the floor, and that the water that flows off the "top" is pumped in from another source that's obscured from view. That's all speculation of course, but one thing's for sure, this is amazingly well done illusion.