Another no brainer is a pipeline to LA from the end of Columbia River at Bonneville Dam. It's brackish after and nobody is using it. That wouldtake a huge load off of Lake Mead.
Canada could be making a shit tonne if water projects weren't taboo.
It should be a no-brainer, but then again Energy East should be a no-brainer and it got mired in politics. I read once that a large scale diversion of the Columbia was on the table for a time. Imagine the politics in play with everyone who sees the Columbia pass through their jurisdiction at the same table? California would have turned to dust and blown away before they could even decide on what to order for lunch.
Water problems in the southwest US is nothing new, it's been in the making since the first settlers arrived in Utah over two hundred years ago. Search out a book titled "Cadillac Desert" (1986) or a four part television documentary of the same name (1997) for some real interesting background. The book is a challenge to find, the documentary streams free on youtube.
One thing that stuck with me is that when water is taken from river systems, the Colorado in particular, to irrigate farmland, as it percolates through the ground back to the river it picks up minerals salts and such along the way. This happens along the entire length of a river to the point where downstream water is so toxic it is no longer usable for irrigation.