The water and the floor both look pretty good!
One crit that I would have to make however is that the rock ruble on the floor could do some work. the cracks in the floor are showing through in some places, and it seems to be going over the walls. the fact that the river is on top of it makes the whole thing seem confusing.
keep it up though, its looking good.
Nice start Bambua, two things I'll comment on...
1. the water, while looking good in the middle, are a bit blurry round the edges, it needs more definition.
2. The rubble shoudn't fade out, either a piece of rubble exists or not - so go in there with magic wand/small eraser and cut the rubble to size