Ocean Shader waves cause ocean plane to pierce through land

Hello,

I’m having problem with ocean shader I’m working on, I use projected grid for vertex placement which I’m later offseting by my wave function offset. My problem is that when coast is not steep enough, for example on beach, waves pierce through land creating effect like shown below. Any ideas how can I fix this, so I can have nice ocean-shore interaction?

http://puu.sh/pQD51/bf6f5af932.jpg