This article talks about conservation measures that are saving Lake Mead water. But square miles of floatovoltaics – solar PV panels floating on water – could save a lot of water by cutting dramatically the amount of evaporation from the surface. Also all the transmission lines and electricity infrastructure are already there because of Hoover Dam. This one is a no brainer. It would take maybe a year or two to build a solar PV array, and get it connected to the grid. One disadvantage of this is that some of the lake would be off limits to recreation and boating. But there is a huge amount of area on Lake Mead.
https://www.sfgate.com/la/article/americas-largest-reservoir-filling-up-19969496.php
