Inflows are currently 60% of average flows. You are right when not if Lake Mead goes dead pool only Vegas will have water from that River behind Hoover dam but they will be fine since the inflows at no point in history have been below 1 million acre feet at the entrance to the Canyon country North of Lake Mead even without any flow from the upper basin Lake Mead still has tributaries below Lake Powell and those have never flowed below 250,000 acre feet even at 50% of normal flows those tributaries supply more than Vegas needs if no water can be taken from Lake Mead when it’s below the outlets at Hoover dam.
All the data you seek.
https://lakemead.water-data.com/
http://lakemead.water-data.com/rivers.php
I’ve been watching water-data.com for years. ;-)
Las Vegas will probably be fine, but everyone downstream who has plans for water to be released from Hoover Dam might ought to be contemplating alternatives.
Pretty much killed the town of Robert Lee that relied on Spence water since their city lake silted up.
The brine water destroyed their pumps and water lines.