thanks for the comments. There are a couple of tricks to waterfalls. The moving water effect is created by slowing down the shutter speed. In these shots it is around 1/10 to 1/13. I use a polarizer to help with light reflections and bring out more color. As you can image to get the best pictures you need good light either early in the morning or later in the afternoon. Therefore I use a Neutral Density (ND0 filter to reduce the amount of light entering the lens. Without the filter it can be difficult to not blow out or overexpose the white of the rushing water. You can also use a smaller apeture to reduce the light, but you would need around f/22 or higher which really dimishes the depth.
Hope this helps, if you have more questions let me know.