Yup, and people do not realize how lucky folks were the Teton Dam collapsed while being filled instead of 130' below the top. The next 100' was a Hell of a lot more water than the first.
There was also similar "bedrock" there that was the problem. And it was volcanic tuff as I recall with better properties than foliated basalt.
Mark Begich, Joaquin Jackson, and Heller resistance... Three huge reasons to worry about the NRA.
