I’m attaching a very good article, longish but clear. This is what it has to say about Goldwater:

Quote
“Before he lost his political career, Goldwater took a trip down to Colorado that was supposed to re-create John Wesley Powell’s famous journey. When he finally retired, after five terms representing Arizona in the US Senate and one failed presidential bid, Goldwater said that the only vote he regretted having cast was the one that led to the damming of Glen Canyon.

“I think of that river as it was when I was a boy, he said. “And that is the way I would like to see it again. “


https://www.newyorker.com/magazine/2021/08/16/the-lost-canyon-under-lake-powell