I think the idea is a huge waste, but the Utah State Legislature already considered exactly this in 2022 (building a massive pipeline to the Pacific Ocean).

https://www.sltrib.com/news/environment/2022/05/19/utah-legi... (archived non-paywall version: http://archive.today/GzuUD)

We really should just figure out how to be sustainable. I also think there is a hard reality people don't want to even consider talking about, which is the Southwest US is too overpopulated and overleveraged for the natural water resources available to it.