To the Joad family, refugees from the exhausted Dust Bowl farmland, with their memories of dessicated soil and the harrowing Mojave Desert they had just passed through, California's San Joaquin Valley must have seemed a paradise beyond their imagining. Steinbeck's descriptive powers are fully a match for the scene below them, each detail further evidence of the goodness of the land; and Winfield's child's-eye view pairs the mystique of the idea of California with the very essence of the real: "There's fruit."

The Joads entered the San Joaquin Valley near Bakersfield, at its southern end. Together with the Sacramento Valley to the north, it comprises the Central Valley, the great flat basin between the Sierra and the Coastal Range, its fertile soil washed down from both sides and enriched by the vegetation of the ages. The 400-mile-long Central Valley is the world's largest agricultural area. It contains nine of the nation's top ten producing agricultural counties, and is the nation's largest supplier of dairy products and the source of over a third of its vegetables and two-thirds of its fruits and nuts.1 Yet most of the annual precipitation in the San Joaquin falls in the winter, leaving the valley relatively dry during the growing months. Thus all of this bounty depends on the Central Valley Project, an enormous water management venture that includes 20 dams and reservoirs and 500 miles of major canals.2

The most recent episode in the area’s long history of water trouble began in 2007. It was a drought year, followed by another, and then another. Farmers pumped groundwater to make up for the lack of surface water. By early in 2009, with snowpack in the Sierra estimated at only 61% of normal,3 the state was promising farmers only 15% of their former water deliveries. By then the aquifer had dropped nearly 400 feet from its 1961 levels,4 and was thought unlikely to recover at any time in the near future.5 Farmers began fallowing their fields, and some almond and walnut farmers, knowing their trees would not survive and that dead and dying trees would bring disease and insects, began to fell groves that were the work of generations. Unemployment rates soared, along with social ills of all sorts. Looking ahead from his vantage point in early 2009, then U.S. Energy Secretary Steven Chu told the Los Angeles Times, "We're looking at a scenario where there's no more agriculture in California." He said he couldn't see how the state's cities would survive.6

That year was followed by a more normal one in 2010, then a truly wet one in 2011, before plunging back into a drought that worsened over the next four years. With each additional year comes the stronger question of whether California could be in a megadrought, one lasting ten, twenty, or more years, with an occasional wetter year. A megadrought would not be new to the state, where the longest known drought, beginning around the year 850, lasted some 240 years. Cornell University Earth and Atmospheric Sciences professor Toby Ault calls megadroughts “the great white sharks of climate: powerful, dangerous, and hard to detect before it’s too late.” He calls them “a threat to civilization,” and foresees a strong likelihood that the southwestern US will experience one in this century.7

California’s water comes largely from the snowpack in the Sierra, which as it melts is stored in a system of reservoirs; and from the pumping of groundwater from the underground aquifers. The impact of dry years on the snowpack is clear, with 2015 chalking up an April 1 reading of only 5% of average; and the levels in the reservoirs had dwindled to well under half of capacity, with some as low as 9%.

Farmers have tried to make up for massive shortages by increasing the pumping of groundwater. But even in wetter years, with the state’s needs persistently exceeding the supply, substantial groundwater is lost. The loss rises dramatically during drought years. Not only is the aquifer steadily depleted, but as water is lost, the land itself subsides. In this newly compacted geology, there is no longer as much space for water to collect, and it is no longer possible for the aquifer to recharge to its former levels.

Governor Jerry Brown declared a statewide drought emergency in 2014, restricting outdoor water use throughout the state. Then in April 2015 he issued a mandate requiring Californians to reduce water use by 25%, a mandate that residents have come close to meeting.

In the meantime, scientists ponder the best approaches to finding the water to keep both people and farm fields supplied. According to University of Arizona climate scientist Gregg Garfin, "If California suffered something like a multi-decade drought, the best-case scenario would be some combination of conservation, technological improvements (such as desalinization plants), multi-state cooperation on the drought, economic-based water transfers from agriculture to urban areas and other things like that to get humans through the drought. But there would be consequences for ecosystems and agriculture," he said.8

The respite brought to northern California by El Nino storms in early 2016 has, for the moment, given that part of the state a little breathing space. Yet there is much reservoir capacity to be made up, and El Nino won’t be around most years to help out.

With new restrictions on groundwater pumping scheduled to begin in 2020, excessive pumping will be reduced. But the state may lose as much as 300,000 acres of farmland. Without skillful land management, and urgent and thoroughgoing action on carbon emission reduction, this acreage could deteriorate into fields of dust that might indeed bring the Dust Bowl to mind. What actions are taken next may determine whether we will see a San Joaquin Valley that would make the Joads wonder why they had bothered to make the trip.

1 U.S. Dept. of Agriculture. California Agricultural Statistics 2013 Crop Year. Apr 2015. https://www.cdfa.ca.gov/statistics/PDFs/CropYearStats2013_NASS.pdf

2 U.S. Dept. of the Interior, Bureau of Reclamation http://www.usbr.gov/projects/Project.jsp?proj_Name=Central%20Valley%20Project.

3 McKinley, Jesse. "Drought adds to hardships in California." The New York Times 21 Feb 2009: A1. Print.

4 Weiser, Matt. "Geological survey finds steep drop in Central Valley's groundwater." Sacramento Bee 13 Jul 2009 http://www.sacbee.com/2009/07/13/2021268/geological-survey-finds-steep.html.

5 Miller, N L; Dale, L L; Brush, C F; Vicuna, S; Dogrul, J; Kadir, T; Cung, F. "Analysis of droughts in the California Central Valley surface-groundwater-conveyance system." California Central Valley Groundwater Modeling Workshop, Berkeley, CA 10-11 July 2008.

6 Haughn, Sarah. "California drought: snowpack inspires consumers, worries water experts." Circle of Blue WaterNews 20 Mar 2009. http://www.circleofblue.org/2009/north-america/california-drought-snowpack-inspires-consumers-worries-water-experts/

7 Rice, Doyle. “California’s 100-Year Drought.” USA Today 3 Sept 2014. http://www.usatoday.com/story/weather/2014/09/02/california-megadrought/14446195/

8 Ibid.