Hmm, there is something wrong with the water that is falling. It makes no sense to me.
Check the image... See how when the water is falling there is no vegetation behind it. It's just wet rocks.
It's personal opinion but i think those waterfalls are letting your matt down right now. They are just too out from the picture.
Or maybe you should work on the spot where they are start falling. Maybe less vegetation there ? So that the river blow the vegetation away, and the water is falling direct in the sea. Also you should add splash effect where the river water meets the sea water ( don't know the exact word for that ... )
Beside that i love the atmosphere !!!
You are getting better.