Jgw - I may have to respond to your post in two or three shots; I just got home.
My biggest beef with Hoover dam is that it created Lake Powell and Lake Mead. In order to do that it drowned Glen Canyon, which should have been left undisturbed as a national treasure. This was a huge loss and a major boondoggle and not enough people know about it.
The idea that we lost such a beautiful area to recreational lakes is appalling. And Powell and Meade are pretty much useless for water retention; they have so much surface acreage that they lose water faster through evaporation than they reserve from the river.
I very much enjoy the Blue Ridge Parkway, in car or on bike, that was a WPA and CCC project,
Blue Ridge ParkwayHoover Damn not such much. But dont worry about Glen Canyon, as it may be reappearing due to the prolonged drought.

The archeological sites are probably gone though, which is a big cultural loss for native Americans, but the Government never really took that seriously, ever!
TAT