The water in Lake Powell, one of the nation's largest reservoirs, has fallen so low amid the Western drought that federal officials are resorting to emergency measures to avoid shutting down hydroelectric power at the Glen Canyon Dam.
source https://www.lifetechnology.com/blogs/life-technology-technology-news/hydropowers-future-is-clouded-by-droughts-floods-and-climate-change-its-also-essential-to-the-us-electric-grid