I first read about the 1976 Teton Dam failure in Cadillac Desert
. Amazing porkbarrel story. Check out this site for more info:
I visited the dam site on the next-to-last day of my cross-country Elefant ride last month. I had to ride down a boat ramp to get to this section of road, which was well under water for a (very brief) time. You can see the intake tower in the upper left-hand part of the picture.