Gradually flatten overlapping vertices on XY-Plane I would like to connect plane with ocean modifier to a flat plane.

I m thinking to keep an x-distance overalapping and i would like to apply a weighted-average that will start moving gradually all vertices of ocean plane to the flat plane.
Does anyone know how that can be achieved?
In link below I have attached the blender file.
https://files.fm/u/rty9tnrz3
Thank you all in advance!
P.S I would like to use this technique for animation purposes
You could select all vertices along the rightmost edge of the ocean, activate proportional editing with a sufficiently large radius and scale to zero in Z-direction.
(Will try to post screenshots later, if necessary!)
In case you want to keep the ocean modifier, you might be interested in using the lattice modifier 
With the lattice vertices scaled to zero height at the right side, the ocean will gradually lose amplitude towards the right. Use the &quot;linear&quot; interpolation to get it totally flat on that side.