“ A canal from the Columbia River or Cascades in the rainy NorthWest to Las Vegas should be a consideration”
Exactly, and if you look at a map, it’s downhill all the way.
????Downhill all the way? The elevation of the Columbia River along the southern part of the river between Oregon and Washington is 0-300 feet (with a few ‘minor’ obstructions between it and the southwest). And they don’t allow even a new orchard to draw water without a lot of permitting hassle (most salmon reasons) so forget it.