I wasn't aware of that one. Interesting. Of course a few years later in 1983 it was so wet, and the water levels behind the dams so poorly managed, that they had to use the spillways on the Hoover dam - running so much flow through them they were significantly damaged.
It would seem mother nature likes her swings around the mean rather than steady state...
Actually it was the Glen Canyon Dam at Lake Powell that had so much volume that year that 4x8 sheets of marine plywood were added to the top of the dam to provide more storage capacity so the dam wouldn’t be overtopped. Spillways had massive erosion which almost led to dam failure. IT WAS A REAL CLOSE CALL.
Read The Emerald Mile by Kevin Fedarko for a great story about running the Colorado River that year in a wooden dory. The story goes into detail on the near catastrophic failure of the dam.