Check out these videos by Scorpion Venom Studio Games about using Physical Water Surface!
Note: During most of these videos the water looks a bit strange. As far as I can tell, this happens because two water planes exist in the level at the same time. At some point in both videos the additional water plane is deleted, making the water surface appear normal again.
watch?v=wLQ9QSJfQsg
https://www…com/watch?v=fEUoAlZz-zo