Good looking scene so far
Like the logs, composition and density colors of the water. A small pity one log penetrates a fake stone.
You might consider to add some bumpy details to the bigger stones.
A way to get a color/displacements half way up the stones is to use a surface layer to control the appearance of the surfacing (use the child-layer input to add more surface layers or powerfractals for more color variations and/or displacements).
Set the altitude and slope on the final normal.
It's going to be a little bit of fiddling but in this image you can use your waterlevel as a reference for selecting your heigth.
I think you're probably going to use this to add darker and wet looking textures on the stones?
Martin
