this looks wonderful!! however, the rocks/cliff in the background look extremely out of place and 2D. a suggestion i have to fix this-
add more shading!! you shaded the basic cracks, but the ledge that holds the waterfall looks extremely wonky without any shading to show that it is protruding from cliff's flat side. the waterfall, as well, needs a little work. it looks like it's going straight down from the top, to the ledge, then suddenly to the side, and is parted by an invisible rock. Since the ledge is flat, the waterfall shouldn't be flowing to the side of it, but down the front and/or pooling from the sides as well. however, if the ledge were tilted, then I would understand why it goes to the side. The rock that is supposed to be parting the waterfall in the middle should have it's top be slightly overlapping the waterfall, and be protruding forward, instead of flat.
over all, a very wonderful drawing with just a few needs of improvement!!