I like the composition. I probably would have cropped out the tree in the top, and the water is slightly blown out. I definitely like this shot though.
nice use of long shutter. personally i would have cropped down to remove the tree, only because the light really emphasizes it and draws the eye out of the pic. nothing much you could have done about the dark water between the foreground and the falls. i think it would have been cooler if it was silver as well to contrast it better from the mossy rock. i guess you would have had to do some creative dodging in photoshop for that.
Well concived and framed shot. It is a shame the backround where most of the action occurs is not as sharp and detail rich as that lovely moss covered rock in the foreground.