This is a good occasion to point to the excellent novel The Water Knife by Paolo Bacigalupi. I think I first heard of it here on HN, and it was described as a "Sci-Fi" novel--sadly, we're approaching the point where we'll have to relabel it as a neo-noir dramatization of current events.

The novel name checks the nonfiction book The Cadillac Desert by Marc Reisner which is also excellent background.

Better would be to eminent domain it, auction it at rates of appropriate economic value and ban water exports outside the states.

All these half measures are no better than doing nothing.