Snowmelt and rain are in abundance for the first time in years in Central Valley, Calif., which boasts so much farmland it helps feed much of the world. But the state's five-year drought was so bad that all those farms sucked up enough groundwater to sink a solid three feet, thereby reducing the region's water storage capacity, reports a new study out of Stanford University. "California is getting all of this rain, but in the Central Valley, there has been a loss of space to store it," says a researcher tells Courthouse News; they used satellite technology to precisely calculate the changes in elevation. "When too much water is taken out of clay, its structure is rearranged at the microscopic level and it settles into a new configuration that has less storage space."
Unfortunately, she adds, that change is irreversible—and extracting groundwater in the future will be harder, "like trying to suck water from a really thin straw." The record-setting drought made things dramatically worse fast, but it isn't entirely to blame; farmers have been over-pumping groundwater for decades, reports the Central Valley Business Times. But as the researchers report in the journal Water Resources Research, there are solutions to the problem, including compelling farmers to draw water from the sandy or gravel layers of earth instead of clay, as they are less likely to permanently compact and replenish more easily through rainfall. Researchers are now trying to map Central Valley's sediment layers to better inform future solutions. (There's more silver lining on the drought front.)