From sea to shining sea may take on a new meaning in California, as state officials are reviewing billion dollar plans to import water from Mexico’s Sea of Cortez to help raise water levels at the Salton Sea.

Formed by floodwaters from the Colorado River, the Salton Sea has been declining for years. Its exposed playa—the bottom of a desert basin—blows in the twisting wind, sending dust into the air and contributing to high childhood asthma rates. The state’s largest water body today is largely fed by agricultural runoff, which has increased salt levels, and the footprint is so reduced...