You might also consider the texture of the water body. In many landscape architecture drawings you will see changes in features highlighted with texture along the shared boundaries. In many cases the highlighting is created by simply making random dots along the boundary. In some historic maps you will see the texture repeated about the entire water body as opposed to just the boundary. In this case, the dots or splotches evoke breaking waves at the surface. This is akin to displaying mountains with little upside down Vs or triangles. While these are nonconventional approaches in the current GIS world, they may have their place in your design.