Creating a terrain with a lake

I would like to know how I can make a lake into a terrain, which I created with the sculpt mode. Especially I would like to know how to create waves, which are rolling on the beach.
I hope you understand what I mean.

if it’s a still frame, you might just want to just model the wave and add a displacement map plus a bump map or two.

If it’s an animation, you can always give the fluid sim a try.

Thanks for your answer.
I think I will try the fluid simulation