The water really looks like it's flowing. I suppose, you could use violet in the shadows(?), to provide a contrast to the green, which otherwise could make the images somewhat monotonous. Violet warms up the picture a bit, because it contains red. The problem is to go from "illustration" to art proper. To paint "beautiful" is simply not good enough. Such a painting is like those beautiful women who are called "bimbos". It means an attractive but boring woman, because she is empty in her head. A painting can be empty because it lacks the soul of the painter. Of course, there is nothing wrong in making beautiful illustrations of waterfalls, but I think one should take artistry a step further.