They knew that spillway would fail if they ever had to use it because concrete in the section that failed was a mess and tons of water would break it apart if it ever had to be used. There was never any doubt what would happen if they every had to use it. They had years of great dry conditions to harden this structure and the problem areas. This was just criminal.
I had a close family member that was part of TVA dam safety and thus FEMA. There are several dams in the US built on the wrong type of rock and many that have not been maintained well and they all know which ones....this is no surprise.
It does seem there’s been criminal negligence of this dam, and likely others.
I grasp only the simplest of engineering principles, so I am speaking from ignorance here, but as bad as it may get, it still is unlikely they’ll lose the dam, right?