Lake Powell officials take unprecedented conservation steps as water level falls

Quick explanation of the layout: Powell divides the Upper and Lower Colorado. These are watersheds with most flow coming from the Upper, and almost all demand in the Lower. Mead is the storage closest to Las Vegas. Those are the largest two reservoirs in the country.

Hydropower generators under Powell could be damaged if the level drops too low. It does generate a tiny amount of the Western grid’s electricity.

Recent article on Arizona: https://news.ycombinator.com/item?id=31139376