well, if yer willing to manually add the falls in, I wouldn't know how to, but, the smudge tool in photo shop would be perfect for it. Many waterfalls you see that are so smoothe in photographs are like so because they were long exposure shots, sometimes a second long. What happenes with that is that while the image is static, the water isn't, so the long exposure cases all the reflections of the water to go together. Because it's moving, it creates a slick blur that causes the smootheness. If you were to manuall drawk the water in, complete with white and blue parts, and smudge them downward, you might get the effect yer looking for sorta. I enver tried it, and I'm sure it'd take awhile to get right, but its worth a shot. otherwise, I wouldn't apply a texture, but rather draw it straight on top of the image. Sucks if you wanna do multiple renders of dif angles, but hey, not always an easy way, lol.