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.

76709-upload-2016-8-22-20-52-0.png

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

Normals were not recalculated. This causes the surface to be perceived as flat one.