Iran and California Face Same Crisis: Pistachio Farms Sinking as Groundwater Vanishes

The pistachio orchards of southeastern Iran and California's Central Valley grow the same crop from the same genetic stock, yet they face an identical crisis that neither region fully controls. Beneath Armin's pistachio farm in Rafsanjan, the earth is literally collapsing. Hand-width cracks spider across his orchard, rupturing irrigation pipes and swallowing water into fissures that open wider each year. Over the past five years, he has watched the damage accelerate. His father and grandfather worked this same land; Armin worries his children will not have that choice.

Rafsanjan has supplied much of the world's pistachios for generations, but the region now ranks among the fastest-sinking areas in Iran. Studies show parts of the ground dropping 37 centimeters annually—more than a foot per year. The cause is straightforward and irreversible: farmers pump far more water from underground aquifers than nature returns. As the aquifer empties, the spaces within it collapse, and the earth above subsides. Armin remembers when wells reached water at just 20 meters deep. Today, many bore down to 300 meters. Some farmland near his has died entirely. Others have been abandoned as wells ran dry.

The connection between these two farming regions traces to the 1960s, when California growers began building a pistachio industry using an Iranian variety called Kerman, named for a city near Armin's farm. California has since overtaken Iran as the world's largest pistachio producer, concentrating most of its crop in the Central Valley. Yet the same problem follows both regions. In California's Central Valley, some areas sink as much as 20 centimeters yearly. Pistachio orchards there use about 4 percent of the valley's total crop water, but in Rafsanjan, more than 90 percent of all groundwater extraction goes to pistachio farming.

Joe Coelho, director of sustainability at American Pistachio Growers, acknowledges the threat. His family has grown the crop since 2000, and while his Fresno farm sits outside the most affected zones, he sees the risk clearly. "Subsidence is absolutely a serious issue in parts of the San Joaquin Valley," he told researchers. As surface water has become less reliable, growers have pumped harder from below. Coelho has witnessed the soil itself change—it no longer holds water or moves it the way it once did.

California and Iran are responding in starkly different ways. In 2014, California passed the Sustainable Groundwater Management Act, requiring water agencies to balance pumping and recharge by 2040. The state is experimenting with managed aquifer recharge—flooding farmland during wet years to store water underground for drought. Coelho participates in one such pilot project. Progress exists: groundwater levels have risen in four of ten monitored wells. But large swaths of the Central Valley still sink. Helen Dahlke, a hydrologist at UC Davis, warns that recharge alone cannot undo decades of overpumping. "Agriculture is by far the largest consumptive use of water in the Central Valley," she notes. Bringing aquifers into balance will require aligning crop demand with the water actually available in a warming, more variable climate.

Iran has no equivalent framework. Ali Beitollahi, who leads subsidence research at Iran's Road, Housing and Urban Development Research Center, emphasizes that land subsidence is entirely man-made—not a natural disaster like an earthquake. "Much of the damage cannot be undone," he says. "When an aquifer collapses, it can never hold as much water again as before." Draft subsidence regulations exist but await government approval. Beitollahi points to Tokyo, where strict groundwater pumping restrictions caused subsidence rates to plummet. He believes Iran could manage the crisis if the state acted quickly, but the current political situation makes swift action unlikely. He calls for immediate changes to irrigation methods—most Rafsanjan orchards still use flood irrigation, losing enormous amounts of water to evaporation before it reaches plant roots—and for farmers to understand why those changes matter.

Armin says he is trying to learn from American growers, but many older farmers resist change. He does not see a future in pistachio farming for himself. Yet when he holds a single pistachio, he sees something beyond a commodity or a snack sold across the world. He sees a tree that may be 100 years old, one that has paid for weddings, for children's education, for the happiness of his family and region. The boom in global demand—driven by food trends like Dubai chocolate—never reaches him. International sanctions and competition have stripped Iran of the markets it once dominated. "We used to be known for quality," he says. "Now we are known for the low price." Coelho, speaking from California's position of relative advantage, frames the challenge differently: "Financial sustainability, water sustainability and environmental sustainability are connected." Both regions will discover whether that connection can be honored before the ground beneath them disappears entirely.