When we set out to do our water footprint for food calculator, we wanted to provide a tool that would allow viewers to understand the water costs of food in a consumer-friendly way. Hence, the plate idea was born.

Nuts aren't typically considered a side to a main meal, so we excluded them from the project. But California is the nation's top producer of several varieties of nuts, so we're breaking out the commercial water footprint for the top three categories where the state is the sole U.S. producer (at least 99%).

Water-use estimates can vary; this report is based on data published by the UNESCO U.S. Institute for Water Education for U.S. averages (full source is info available at the bottom).

Almonds

Almonds (shelled) are the third-most-valued commodity in California, and the No. 1 agricultural export from 2010 to 2012, according to the California Agricultural Statistics Review 2013-2014. In 2014, $6.5-billion-worth of almonds were produced on 860,000 acres, primarily in Fresno, Kern and Stanislaus counties. Top export markets included the European Union, China and Hong Kong, and Japan.

Walnuts

Walnuts were California's ninth-most-valued commodity and ranked fourth in exports from 2010 to 2012. In 2013, 290,000 acres produced $1.8-billion-worth of walnuts, according to the National Agricultural Statistics Service. San Joaquin, Butte and Stanislaus counties are the leading producers. Top export markets include China and Hong Kong, South Korea and the United Arab Emirates.

Pistachios

Pistachios were California's eleventh-most-valued commodity and fifth-highest export from 2010 to 2012. Kern County produces more than 40%. In 2014, 215,000 acres produced $1.3-billion-worth. Major export markets in 2012 included the European Union, China and Hong Kong, and India.

Nuts compared with meats

So how do nuts stack up to meats? When comparing the global average water footprints, nuts overall have a far lower water footprint when looking at per ton and calorie rates, especially when compared with beef, according to a report on the water footprint of animal products which you can download in full here.

"Replacing all meat by an equivalent amount of crop products such as pulses and nuts will result in a 30% reduction of the food-related water footprint of the average American citizen," water experts and authors of the report, Mesfin Mekonnen and Arjen Hoekstra say.

Source: M.M. Mekonnen and A.Y. Hoekstra (2010), "The Green, Blue and Grey Water Footprint of Crops and Derived Crop Products," and "The Green, Blue and Grey Water Footprint of Farm Animals and Animal Products," Value of Water Research Report Series No. 47 and 48, UNESCO-IHE, Delft, the Netherlands.

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