It's not (very) disruptive if you build an artificial closed-cycle lake on an existing elevation difference. But such sites are not very commonly available wher

It's not (very) disruptive if you build an artificial closed-cycle lake on an existing elevation difference. But such sites are not very commonly available where storage is needed. You have to refresh the water to compensate for evaporation, and that's about the extent of the impact. Dammed streams of course are a completely different story.