Which California Crops Are Worth the Water? Check for Yourself

As the historic drought continues, see which top export crops are efficient at turning water into nutrition—and which aren't.

A crop’s water footprint—–all the water needed to grow and process it—–is one way of measuring its water efficiency. But there is more to the picture than just how much water is used to produce every pound of a crop. Comparing the nutritional value of each one, you can see which crops provide the most bang for your buck, or in this case, the most bang for your gallon.
Almonds have a high water footprint. They’re not very efficient when it comes to gallons of water used to produce one pound, but they make up for some of that high water use when you consider gallons per grams of protein and kilocalories (one thousand calories) produced.

Cherries have a relatively small water footprint compared with almonds, but nuts are much more nutritionally efficient, producing more protein per gallon of water used.
Nuts, cherries, and peaches grow in trees and must be watered year-round. They have a large water footprint per unit of edible plant, unlike crops where nearly the whole mass is consumed, such as spinach. Leafy greens, while nutritious, just don’t pack a lot of calories.
Raisins have a much bigger footprint than grapes. They use the same amount of water to grow but result in less product after the drying process. Processed foods like canned tomatoes and fruit cocktails also have larger water footprints than their raw form.
On this scale, rice doesn’t have a glaring inefficiency. But among California’s top export crops, only nuts rank higher. Rice fields are continuously irrigated during their growing season but not year-round.

Take a look at the efficiency triangles of the rest of California’s top export crops and see which make the best use of water.
Unprocessed crops for human consumption
Unprocessed crops for human consumption

California’s thirstiest crops are under scrutiny amid the state’s severe drought. At the center of the debate are permanent crops, like almonds, that require year-round watering.

With agriculture responsible for roughly 80 percent of California’s water use, many question the practicality of crops that cannot be fallowed and the viability of producing food for export.

A crop’s water footprint—all the water needed  to grow and process it—is one way of measuring its water efficiency. Almonds, in particular, have been criticized for their high water footprint, since they are one of California’s most water-intensive crops.

Around two-thirds of almonds are exported, making them the state’s leading export crop. Some critics disapprove of California sending so much virtual water to other countries in the form of food and animal feed irrigated with that water. Others have defended the growing of highly nutritious crops like almonds, noting their calorie and protein content is worth the amount of water use.

So how do California’s top export crops actually stack up when you factor nutrition into the water efficiency equation?

To answer this question, this graphic analyzes California’s top export crops as determined by the University of California, Davis. Water footprints for each crop were gathered from the Water Footprint Network, and nutrition data were obtained from the U.S. Department of Agriculture.

The intention is to compare each crop’s relative efficiency at turning water into edible material, calories, and protein. (Other important nutrients, such as vitamins, minerals, fatty acids, and antioxidants, were not considered for this ranking.)