Light on water surface

I'm trying to develop water surface. I have a simple plane and in time I'm moving vertices to generate waves. On top of the scene I have a directional light.

The only problem I have with current solution is that I do not see the waves itself because they are of the same color for me. Usually, if you have a light and the surface that is changing it's angle then there should be light reflections and the color must be either brighten or darken.

Did I miss something in my implementation? Or it is ok and I have to implement shader on top to reflect this behavior?