This article points out the obvious — since future supply is falling, the change in future demand will determine how bad the shortages are:

The water plan predicts that California’s mean temperature may rise 1.5 degrees to 5 degrees Fahrenheit by 2050, which could lead to an increase in water demands, particularly for agriculture. Temperature increases could also increase evaporation, which could lower stream flows and concentrate agricultural run-off and urban wastewater discharges.

Based on this data, combined with models for population growth, government action and changes in technology, the water plan predicts three basic scenarios for water use statewide.

[snip]

In one scenario, with expansive growth and minimal action, the state water plan predicts that by 2050, the state of California will need an additional 11 million acre-feet per year to satisfy demands. A middle-of-the-road scenario sees slightly slower population growth, but a drastic decrease in farming that reduces water demand, and predicts a 6 million acre-feet increase in demand. With conservation efforts and strong action, that estimate drops to only needing an additional 2 million acre-feet.

I am hoping that they have a chapter on using prices and markets to manage demand.

Bottom Line: We are all going to die — unless we start treating water like the scarce commodity that it is