How to select the reflections only on a scene with water?

NorthShoreArchitect

Hi, I would like to know how to select the reflection on the wate on the scene plus the architecture so I can add both to an image I already have of where this structure actually goes. Does anyone know how to select only the reflection in the water, I've tried the reflection channel but no success.

Test quai.png

eidam655

i assume you render with VRay - since Reflection channel didn't help, you could try Raw Reflection.

but maybe an easier way would be to remove the color from the sea and leave it white - that way the bumps would stay but you would have no problems with selection.