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Storm Runoff May Recharge Aquifers and Your Crops
Almond Board |

When it comes to water scarcity, California offers researchers a perfect laboratory. The historic drought it endured over the past few years began impacting groundwater levels, leaving farms few options but to drill deeper and deeper for lower-quality water. Enter Helen Dahlke, Assistant Professor in Physical Hydrology at University of California, Davis. She headed up a study on how to tap into storm water and winter melt runoff in a way that would not run afoul of California’s strict water rights or environmental laws. The team wanted to learn how much of the water that was redirected onto the test sites made it below the root zone and into the water table, and if flooding dormant crops had an impact on the next season’s yield. Dahlke said, “We have done on-farm experiments on alfalfa, almonds, and pistachio. But many other cropping systems would most likely work as well. We just didn’t have the chance or funding yet to try it out on other crops.” The results of the University of California, Davis study are intriguing: First, water was indeed penetrating to a deeper level. “Results from our two on-farm experiments indicate that an astoundingly large fraction of the applied winter water percolated past the root zone and was moving toward the groundwater table,” Dahlke wrote in a paper she presented to her colleagues at the 2017 California Plant and Soil Conference. “From the tested winter water application amounts (which ranged between 4 feet and 6.7 feet at the Davis site, and between 2.6 feet and 26 feet at the Scott Valley site), more than 90% of the applied water went to deep percolation.” Even more promisingly, this method of agricultural groundwater banking seems to have a positive impact on crops, rather than a negative one.

About the Almond Board of California

Almonds from California are a healthy, natural, wholesome and quality food. The Almond Board of California promotes almonds with a research-based approach to responsible farming, production and marketing on behalf of the more than 7,600 almond growers and processors in California, many of whom have third- and fourth-generation family operations. Established in 1950 and based in Modesto, California, the Almond Board of California is a non-profit organization that administers a grower-enacted Federal Marketing Order under the supervision of the United States Department of Agriculture. For more information on the Almond Board of California or almonds, visit or check out California Almonds on Facebook, Twitter, Instagram and the California Almonds blog.