C&C per req:
I'm going to deal with these more as a group than individual images. First off, in several (Notably 1, 2, 5, 6, and 8) the white balance appears drastically out. The images are far too blue; the WB needs to be much warmer, especially given that shade is prevalent in most of your images.
3,4 7, and 8 all suffer from serious under-exposure in the shadow areas. You've done a good job of getting the highlights exposed, but the dark areas are virtually without detail. The only way to really capture these images successfully is going to be with fill light. I'm not sure how far you were away, but an off-camera light-source would have made a huge difference.
One of the tricks with this type of photography is knowing how long an exposure is correct. This varies with the flow rate of the water, and I've used anywhere from a 1/2 second up to 4 or 5 seconds. Since there's no exposure data in your EXIF info, I don't know what your settings were, but #3 is right at your maximum. You have just a bit of detail in it, but you can see it's verging on being nothing but a white highlight area. Another half second and it would have been lost.
Always be congnizant of your background and surroundings. In 3, 5, and 7 you have leaves, branches, and other detritus which doesn't add to the picture.
Of all of the images (WB notwithstanding) #6 is IMHO, the best one. Had you been standing another couple of feet to your right, I think it would have been even better, but as is, it's still very good.
When you're doing this sort of work, don't forget you need to pack a few extras in addition to your camera and tripod. One is a cover for your camera, even just an old shopping bag to keep the spray off of it. Another is extra lens cloths, as you'll have to wipe the front element frequently, and lastly, either very tall boots or preferably hip-waders. It's been my experience that the best shots always require you to get into the water.
Something else you may want to invest in are neutral density filters to allow you to get even slower shutter speeds.