yes, that's trillions
Using satellite data, NASA has determined that it will take 11 trillion gallons of water for California to recover from its drought — about 1.5 times the maximum volume of the largest reservoir in the United States.
The data came from NASA's Gravity Recovery and Climate Experiment (GRACE) satellites, and it's the first ever calculation of the volume of water needed to end a drought. "Spaceborne and airborne measurements of Earth's changing shape, surface height, and gravity field now allow us to measure and analyze key features of droughts better than ever before, including determining precisely when they begin and end and what their magnitude is at any moment in time," NASA scientist Jay Famiglietti said in a statement.
GRACE data has found that since 2011, the Sacramento and San Joaquin river basins decreased in volume by 4 trillion gallons of water every year, which is more water than the state's residents use annually. While recent storms have made a slight dent in the drought, it's not nearly enough. "It takes years to get into a drought of this severity," Famiglietti said, "and it will likely take many more big storms, and years, to crawl out of it."