Long thread on Lake Mead water levels, trends, etc.
As to Lake Mead, it’d take a decade of above average rainfall / snowmelt to refill it. Maybe even 2 decades. Meanwhile to climatic trend is drier, not wetter.
As to the burgeoning headcount in the Southwest, yeah, it’s a problem. But the electricity from Hoover Dam is small potatoes; what matters to Vegas and the entire desert southwest is water. Power can be shipped in from anywhere. Water not so much.