Is there anything even heroic that could be done... like shipping trainloads of snow down from the north next winter?
Most people do not realize how cheap water is and how much it weighs. I saw in another article that Los Angeles is paying $700 per acre foot for water from farmers. I looked it up and one acre foot is about 1000 cubic meters. I cubic meter is 1000 liters and one liter of water has a mass of 1 kilogram so one acre foot weighs around 1000 tons. No way you are going to ship 1000 tons of water a long distance on a train for $700. BTW to compare, a battleship weighs around 50,000 tons or as much as 50 acre feet of water. Even with the drought some farmers are getting about 1 acre-foot of water per acre per year. So a 50 acre plot of land gets water with weight equal to a battleship.