Although I use a stack of transparent layers to emulate realistic water features - especially simulating depth in water. In looking at your water feature, the only criticism I have is that you have waves going on in your little lake. Unless there is a powerful underwater current feeding this pond, or some other magical reason, the water should be still with no wave action at all. If it were a larger outside lake, then your turbulent water surface would be fine, but in a cave...? There shouldn't be anything disturbing the water suface. Otherwise you seem to use many of the techniques I do - use of bevels, shadows, etc.