If you bring water in from the rest of the US and supply the regions which depend on the water flowing down from the mountains you allow the high altitude regio

If you bring water in from the rest of the US and supply the regions which depend on the water flowing down from the mountains you allow the high altitude regions to retain more of their water. Sure, that means you generate less hydropower in the downriver dams, but overall I think it's a wash(pun intended).