Why California needs more water than ever to end its drought

The "drought" is not entirely a natural phenomenon. When people were working out the water rights they had an optimistic view because this is how people could get the most in the short term.

Expectations for water availability were too high. I'm amused that the article describes the situation as "unimaginable" because many critics of the Colorado River dam scheme in the 1960s thought the dams could effectively fail in a 40-100 year time span.