To obtain an image reflected on the water using Adobe Photoshop, proceed with the following steps.

Copy the image on the water, cutting the part that won't be visible (remember that objects are three-dimensional).

Copy the image on a new layer and reflect it vertically by Edit > Transform > Flip Vertical.

Create a new blank document of the same size of the original one, that will be used for the water rufflings.

1. Select the black color for the foreground and white for the background.
2. Use Filter > Sketch > Halftone pattern to create a texture of horizontal lines (the lines size depends on the rufflings that are needed).
3. Blur the lines with Filter > Blur > Gaussian Blur.
4. Save the new document in PSD format.

Go back to the original photography and use Filter > Distort > Displace applying the rufflings file just saved.

Using Filter > Liquify, work on the rufflings to perfect them (otherwise they will be too regular) and distribute the reflection around the cut subject.
At the end of the process blur the reflection.

Work on the reflection, desaturate it and adjust the layer opacity: the parameters depend on the clearness of the water.