>>It would be interesting to see a video of that, to see if they are in fact bubbles.<<
I watched the video. I saw the bubbles coming up and bursting. I captured some of the video into images (this is one of them). I’d have to search for the video source if it is online still.
Not reflections.
What was interesting is the helicopter camera operator was in a wide angle view of the whole dam. Then he saw these huge bubbles coming up. That is when the operator zoomed in to this view. So they too saw the action.
I’ll take your word for it.