That's a very cool atmosphere

Is it heavily post-processed or almost straight from TG?
Personally I don't really like the way TG renders reflections and recently I have consistently switched to rendering soft reflections for the water.
You may have a look and see how it works for your render here. I'd recommend to start with a softness of just 0.005 and 4 reflection samples (should be sufficient).
Cheers,
Martin
PS, In case you don't know how to set it up, but I think you do though: disable reflections in water shader, connect reflective shader in between water shader and lake object and set the reflections to be raytraced + the settings I suggested.