Please clairfy your question a bit, The way you make water look like it is lower than the surrounding land is to, create a hole or a depression in your terrain. You position the terrain to be used as the ocean floor higher than the ground plane. And your water is a seperate flat object. siting on to of the ocean floor terrain. You do not use the ground plane as your water. Many delete this and never use it at all. As least I think this is what you wanted to know.