If the whole river is in view (ie from above) then most people probably would not do the reflections in realtime.
If it is for a FPS-type game or overhead cam game, where only sections of the river are seen at a time, then it can be done dynamically. In this case, your answer is simple: How does a boat travel a snaking river? I'd set up camera waypoints along the river so that it can be done dynamically relative via the player/cam position.
If it is for a FPS-type game or overhead cam game, where only sections of the river are seen at a time, then it can be done dynamically. In this case, your answer is simple: How does a boat travel a snaking river? I'd set up camera waypoints along the river so that it can be done dynamically relative via the player/cam position.