Well, it looks like the view the “sunlight reflection” of a couple days ago was really a breach in the sidewall of the main spillway. The main spillway is like a H with the main water flow groove, and a side wall on both sides to keep the water flowing down the central channel.
If I understand what I am seeing here, up above the original “hole,” back towards the spillway top, on the left side, you had a FAILURE of some of the concrete wall sections. This allowed the water to DIVERT from the main “channel, and shift left OUTSIDE THE CONCRETE CHANNEL, AND START ERODING, DIRECTLY ERODING THE DIRT THAT IS RIGHT NEXT TO THE SPILLWAY. The situation is you now have TWO SEPARATE DOWNSTREAM WATER FLOWS: THE FIRST ONE INSIDE THE SPILLWAY AND THE SECOND ONE EXITING THE WALL BREACH AND ERODING AWAY THE HILLSIDE, OR EVEN GOING BACK UNDER THE MAIN SPILLWAY AND CAUSING FURTHER DAMAGE TO THE CONCRETE SLABS ETC.
Yep, it is now a done deal in my opinion. The failure of the main spillway is now INEVITABLE. It will eventually fail, all the way from the sidewall breach, the one between/below the power lines, and the top of the spillway.
The erosion undercut going back up towards the spillway top, on the left side first, a day or so ago, and IT IS LIKELY CUTTING UNDER THE ENTIRE WIDTH OF THE MAIN SPILLWAY AND WILL LIKE CAUSE A SEPARATE BREACH ON THE RIGHT SIDE OF THE SPILLWAY WALL. (Click to Article)