California Agricultural Production and Irrigated Water Use

California ranks as the leading agricultural state in the United States in terms of farm-level sales.  In 2012, California’s farm-level sales totaled nearly $45 billion and accounted for 11% of total U.S. agricultural sales. Five counties—Tulare, Kern, Fresno, Monterey, and Merced—rank among the leading agricultural counties in the nation.

Given current drought conditions in California, however, there has been much attention on the use of water to grow agricultural crops in the state. Depending on the data source, irrigated agriculture accounts for roughly 40% to 80% of total water supplies. Such discrepancies are largely based on different survey methods and assumptions, including the baseline amount of water estimated for use (e.g., what constitutes “available” supplies).

Two primary data sources are the U.S. Geological Survey (USGS) and the California Department of Water Resources (DWR).  USGS estimates water use for agricultural irrigation in California at 25.8 million acre-feet (MAF), accounting for 61% of USGS’s estimates of total withdrawals. DWR estimates water use withdrawals for agricultural irrigation at 33 MAF, or about 41% of total use. Both of these estimates are based on available data for 2010. These estimates differ from other widely cited estimates indicating that agricultural use accounts for 80% of California’s available water supplies, as reported in media and news reports.

Attention has also focused on trends in California toward growing more permanent orchard crops, such as fruit and nut trees and vineyard crops, as well as production of grain and pasture crops, much of which is used to support the state’s meat and dairy industries. Orchard crops refer to tree or vineyard crops that are planted once, require continuous watering to reach maturation, and cannot be fallowed during dry years without loss of investment. In contrast, most vegetables and other row crops (including grain and pasture crops) are annual crops that are sown and harvested during the same production year, sometimes more than once, and may be fallowed in dry years.

Between 2004 and 2013, overall harvested acres in California increased for almonds, walnuts, pistachios, raisins, grapes, berries, cherries, pomegranates, and olives, but also for corn. During the same period, overall harvested acreage decreased for some field crops (cotton, alfalfa, rice, wheat), but also for certain orchard crops (wine grapes and some citrus and tree fruits). This shift to growing more permanent crops, especially tree nuts, appears to be largely market-driven.

The availability of irrigation water has been a major factor in the development of California’s agricultural production. California has the largest number of irrigated farmed acres compared to other states and accounts for about one-fourth of total applied acre-feet of irrigated water in the United States. Water use per acre in California is also high compared to other states. Available data for 2013 indicate that, of total irrigated acres harvested in California, about 31% of irrigated acres were land in orchards and 18% were land in vegetables. Another 46% of irrigated acres harvested were land in alfalfa, hay, pastureland, rice, corn, and cotton.

Congressional interest in California agriculture and water use centers largely on the Bureau of Reclamation’s Central Valley Project (CVP), which supplies water to numerous agricultural and municipal contractors. In recent years, the CVP has cut back water deliveries due to drought and environmental factors. Congress also authorizes and oversees U.S. Department of Agriculture support for individual crops and farmers, and some Members have expressed concern over the broader implications of decreased agricultural production and/or lack of water availability throughout the state.