Thanks for posting that. It was MUCH more informational. Sounds like it is nothing to get bothered about. It is not holding back water. It is just a really big speed bump in the spillway to slow down the water to reduce erosion downstream. Even if it fails, it is not going to collapse downstream dams.
It may or may not overstress dams downstream but it will flood people if it does break. Spillways hold back entire lakes. It will also cause power outages as flooding will damage electrical generation. Expect more of this to begin to hit the headlines in the near future as these dams and structures move past their 50 year projected lifetimes. It would scare the public if they knew how many dams have huge cracks could break at any time.