Here is a little example blend-file about how i made the water reflections with refractions for the Winter Environment 1 scene.
The basic mountains which I used for this scene, were generated in Blender-2.80 with the awesome landscape tool.
The water object has two surfaces with different materials.
* The upper water surface for the reflection has a material with dithered opacity (0.215) named Alpha Hashed in Blender 2.8x
* The lower water surface has the material for the refration, in Blender its Alpha Blend