Wall Street is thirsty for its next big investment opportunity: The West's vanishing water

Situated in the Sonoran Desert near the Arizona-California border is the tiny rural town of Cibola – home to roughly 300 people, depending on the season. Life here depends almost entirely on the Colorado River, which nourishes thirsty crops like cotton and alfalfa, sustains a nearby wildlife refuge and allows visitors to enjoy boating and other recreation. It’s a place few Americans are likely to have heard of, which made it all the more surprising when investment firm Greenstone Management Partners bought nearly 500 acres of land here. On its...