California Almond Water Footprint
University of California, Davis
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The domestic and international media have recently focused on the water footprint of California almonds and have related the water footprint to water use and the drought. The water footprint is an index of the complete use of and impacts to water systems. It is the sum of water impacts from production of a good or service used by people. It is typically expressed per unit production, per region, or per capita. It goes beyond consideration of water use (e.g., from irrigation) and according to the International Standards Organization is similar to the life cycle analysis approach. Besides the problem of perception that California almonds have a large water footprint, there is the additional problem that the water footprint estimate quoted in the media is not accurate and has gradually improved over time. Finally, the many nutritional and economic benefits that almond production and almonds provide are lost in a water footprint calculation that report volume of water per unit weight of almonds. Almond production provides a large economic and employment benefit to California. Almonds are also high in food value, especially relative to other high water footprint foods, such as beef. We are calculating the water footprint in terms of economic benefit, protein (g), or total food benefit in order to provide a better representation of the benefits of almonds relative to the water footprint. Almond water footprints show a great deal of variability around the state based on yield, evapotranspiration (ET) rates, and recently updated crop coefficients (Kc). The lowest almond water footprints are in the southern San Joaquin Valley and the highest are in the northern Sacramento Valley. This is due primarily to differences in yields between north (low) and south (high). However, the agricultural water sources and water quality concerns that are present in the north vs. the south are also quite different. While current estimates of an average almond water footprint may be only slightly (+20%) revised by this research, we find almonds to have economic and health productivity advantages over other crops commonly grown in the region. Further, we see potential for management actions that reduce water footprints synergistically with greenhouse gas and other ecological footprint indicators.