Looking through the manual (I only got it last night), there seems to be a lot of options in the SmartGraph function editor relating to water. One input node is "Distance to object below", which looks like it should be useful for controling the distribution of a mixed material to give a bias towards one of the materials as water depth diminishes. There is of course the "Open ocean" node specifically for creating waves, and also lots of interesting looking Turbulence nodes. So I can envisage a material which uses Open ocean for deep water blending into a tubulence based material as shore gets nearer and then a foamy material at very shallow water. Probably going to take a lot of experimenting, but it looks achievable.

Mark