2D Water top surface profile

I am trying to create the effect of the water surface thickness with a vertex-fragment shader.

I am in a 3D game environment but It’s a scroll view so a “2D” view.
Here is a good tutorial of creating such effect in real 2D using fragment shader.

But this can’t be used in my case I think.
For the moment I have only a plane were I apply refraction.


And I want to apply the water thickness effect. But I don’t know how to do it.

I am not trying to create some water deformation/displacement using vertex for the moment, this is not the point.

I don’t know if it’s possible with a simple quad maybe should I use an object like this.


Here are some examples.


I don’t have any idea on how to create this effect.

Thanks a lot !

[EDIT] Added Rayman water effect to have a better reference of the effect.

I made a 2D water material that might interest you. It has animated waves, a refractive (glass) shader, water splash FX, and an example of buoyancy physics. The material does not require Unity Pro, and the shader works on mobile platforms too: Water 2D Kit | 2D Water | Unity Asset Store