You could start with a plane or a ground and make the following adjustments to the object default attributes:
COLOR REFLECT FILTER SPECULAR R 0 100 0 255 G 255 120 0 255 B 255 140 0 255 Dithering Hardness Roughness Shininess 0 125 (Or more) 20 0
Then apply BUMPNOIZ texture as follows:
Column One Two ____ ____ 100 0 20 0 10 0 0 0 0.6 0 0 0 0.2 0 0 0
Bump-mapping and bump textures do not modify the geometry of the object; they simply add highlights and shadows as if the object _were_ bumpy. Your lake would still remain a flat plane, with no points to stick out.
You should position the primary light source in front of the camera to obtain specular highlights.
Maybe this is not very helpful, but I thought You might find DINOSKIN texture useful in this case too. It is a very flexible texture which can produce loads of other kind of surfaces than dino skin. The shape of the bumps can be modified to a great extend by adjusting the noise values. Also, You have control of how "widely" the bumps are colored by adjusting the color clip value. So You can certainly make some kind of whitecaps with it without having actual modelled bumps in the object.