Definitely go with Scott's solution. It may take some tweaking of materials and the altitude filter in the DTE to get what you want but it's well worth it. I added some abience to the water material and TIR since light bounces all around in water. And to get the sand darker at the water's edge I just copied the G2h and brought it into photopaint then smeared the darker areas further into the light area until I got it where I wanted then used it in the diffusion value channel.