There is no such option unless you build your own wave system.
You can try to figure out what the ocean uses for wave calculations.
If you manage that, maybe you can modify or duplicate the function to return height values for you.
You want Z for X and Y at Gametime.
The post process doesn’t really need to know the height. It probably detects the water sheet with a stencil or similar to bring the effects into place.
Wouldn’t bark up that tree even if it somehow did.
Maybe you can fake this by placing a buoyancy pontoon on an invisible object that’s attached to the player but free to respond to waves. Then read off its Z value.
The cost of that is literally insane compared to what you need, so i wouldnt reccomend it outside of testing that your own wave reading solution is accurate…