Would love if the river material was responsive to its surroundings, so when you add a rock in the river, it creates water foam and ripples around it (based on the speed of the river).
If that is not possible, even the addition of ripples would be enough for us to add the effects on top of it, or even use it in a complex format where lots of human construction is overlapping a flowing river.
This video best describes the effect: Distance Fields (Part 1) | 5-Minute Materials [UE4/UE5] - YouTube