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Searching for Answers in the California Drought

May 28, 2015
The ongoing drought in California presents a significant policy challenge to state and federal lawmakers. In an environment where critical allocation decisions must be made, understanding the source of California’s drought is important. Here, we look at the ways that water is used in California and show that searching for the source of water shortages in the state ought not to be reduced to the question of who uses the most water. Rather, a more comprehensive appraisal of the situation requires putting the drought into a historical context of California’s growth over the past century in a dynamic climate.


The plight of the state of California in the midst of a historic drought since 2012 has been well documented. As the drought enters its fourth year, the challenges of the state remain immense, and the effects upon California’s citizens continue to grow. Governor Jerry Brown declared a state of emergency in 2014, and earlier this year, he signed an executive order mandating a reduction in urban water use of roughly 25%. [1],[2] Some municipalities have taken even more aggressive action in light of the drought; San Jose has imposed a mandatory reduction of 30% in water usage by residents. [3] 

Naturally, the challenges of the drought have brought on a series of assertions about the causes of the water shortage. The drought is a result of reduced rainfall, but are California’s water resources allocated in an entirely optimal fashion? In attempting to assign blame for the dearth of water, many have evaluated the ways that water in California is consumed to identify what is driving the shortage and where savings can be identified.

Of course, much has been made of the water used by urban areas of California. A study with 2005 data found that urban Californians used on average 124 gallons of water each day, a number that is well above the national average among states. [4] Nevertheless, data on water usage suggest that in recent years Californians have begun to increasingly restrain water consumption.  Water usage by urban and residential areas has not risen in the past 20 years, even though the population has increased during the same time period. [5] Moreover, according to a frequently cited report from the Public Policy Institute of California, residential and urban usage represents just 10% of the share of total available surface-level water. [5]

Agricultural usage of water has also been scrutinized in the midst of the drought.  Agricultural consumption of water does in fact utilize a massive share of water resources in the state; agricultural sources use roughly four times more water than the urban and residential utilization. [5] Nevertheless, agriculture represents a sizable component of the California economy; in 2014, economic costs from the drought’s effects largely in agriculture were estimated at around $2.2 billion and 17,100 lost jobs. [6] As a result of the constraints imposed by rainfall conditions, farmers have moved increasingly to efficient irrigation techniques that have stabilized agricultural water usage over the past decade despite higher crop outputs. Furthermore, though the agricultural share of surface level water available is massive, it constitutes just a 40% share. [5]

The remaining 50% of surface level water in the state of California that does not go to urban, residential, or agricultural purposes, is left to environmental purposes. Motivations behind such policies can include the protection of endangered species of fish or the preservation of fragile biospheres. However, bodies of water can also be protected with the goal of maintaining water quality for agricultural and urban uses. Nevertheless, the allocation of 50% of the state’s surface level water resources has been questioned as optimal in the wake of a drought that has impacted so many in California.

Is environmental policy to blame for severe water shortages in the California drought?

While it is undoubtedly true that environmental usage of water represents a large fraction of available surface-level water, it is certainly not clear that environmentally protected waters should be labeled as a dominant cause of the water shortage. Citing the total environmentally devoted share of surface-level water available is in some ways slightly misleading in assessing the role of environmental policies and regulations in inducing a shortage of water. The bulk of the water devoted to the environment (over 50%) is along the northern shore of California where other agricultural and urban uses are not feasible. The Public Policy Institute of California finds that in areas where agricultural use and urban use also exist, water devoted to the environment represents just a 33% share, versus a 53% share for agriculture and 14% share for urban uses. [5]

Beyond Water Usage: the Drought in Historical and Environmental Contexts

Though the current drought in California may be the driest since the first recording of such data, the drought is certainly not the first of its kind. Notably, the state suffered from severe droughts between 1929-1934, 1976-1977, 1987-1992, and even as recently as 2007-2009. The severity of some of these droughts in terms of rainfall was comparable to the current drought seen in California. Indeed, the drought of 1929-1934 marked a six-year period of dry conditions that occurred in the context of the wider Dustbowl conditions across much of the western United States. The drought of 1976-1977 until 2014 featured the driest year (1977) and tenth driest year (1976) on record. [7]

However, while the levels of rainfall can be related to the current drought, the challenges of today’s drought in California are fundamentally different. In 1930, California’s population was just 5.7 million, and even during the 1987-1992 drought, the California population was just about 80% of where it stands today. Another notable difference with the current drought is tied to the markedly increased temperature levels. With some of the hottest years on record over the past decade, snowpack in the mountains of Northern California has been lost, diminishing available water further; as such, climate change has exacerbated the current drought and likely threatens to increasingly do so with future droughts. [8] Beyond record-low rainfall, the combination of an increased population and climate change has given this drought a unique place in the history of California droughts.

In this way, the difficulties of California’s current drought are rooted not just in high agricultural use, extensive environmental protections, or excessive urban consumption of water. Rather, the current drought also represents a confluence of increased demands in the context of a dynamic statewide climate. Scientific research over the last two decades has revealed that California may have faced “Megadroughts” with extreme dryness and durations on the orders of centuries in the past. [9] It is not clear that a megadrought is on hand or likely in the near future, but the existence of extreme periods of drought suggests that the past century in California may not offer a truly representative sample of California’s long-term climate. [10]  The development and growth in California over the past century may then have been based upon an inappropriate set of assumptions about rainfall in the state. The persistence of the current drought and of other droughts to come in the following decades may perturb the understanding of what level of water demand the state can sustain. One study found that in the event of a mega-drought lasting over seven decades, California would eventually reach an equilibrium of water use, but not before there were significant impacts on agriculture, urban use, and the environment. [11] The challenge for policy-makers in the current drought and droughts moving forward will be to take the necessary actions to adjust to shifting environmental and climate pressures.



  [1] Chappell, Bill. “California’s Governor Declares State of Emergency.” NPR, January 17, 2014. http://www.npr.org/sections/thetwo-way/2014/01/17/263529525/california-s-governor-declares-drought-state-of-emergency

  [2] Megerian, Chris, Matt Stevens, and Bettina Boxall. “Brown orders California’s first mandatory water restrictions: ‘It’s a different world.’” LA Times, April 1, 2015. http://www.latimes.com/local/lanow/la-me-ln-snowpack-20150331-story.html#page=1

  [3] Kurhi, Eric. “San Jose adopts 30 percent water reduction goal.” San Jose Mercury News, April 21, 2015. http://www.mercurynews.com/drought/ci_27960479/san-jose-looks-adopt-30-percent-water-reduction

  [4] Kearney, Melissa S., Benjamin H. Harris, Brad Hershbein, Elisa Jácome, and Gregory Nantz. “In Times of Drought: Nine Economic Facts about Water in the United States.” The Hamilton Project, October 2014. http://www.hamiltonproject.org/papers/in_times_of_drought_nine_economic_facts_about_water_in_the_us/

  [5] Mount, Jeffrey, Emma Freeman, and Jay Lund. “Water Use in California.” Public Policy Institute of California, July 2014. http://www.ppic.org/main/publication_show.asp?i=1108 

  [6] Howitt, Richard, Josué Medellín-Azuara, Duncan MacEwan, Jay Lund, and Daniel Sumner. “Economic analysis of the 2014 drought for California agriculture.” Davis, CA: UC–Davis Center for Watershed Sciences. Online at https://watershed.ucdavis.edu/files/biblio/Economic_Impact_of_the_2014_California_Water_Drought_1.pdf.

  [7] California Department of Water Resources. “California’s Most Significant Droughts: Comparing Historical and Recent Conditions.” State of California, February 2015. http://www.water.ca.gov/waterconditions/docs/California_Signficant_Droughts_2015_small.pdf

  [8] Swain, Daniel L., Michael Tsiang, Matz Haugen, Deepti Singh, Allison Charland, Bala Rajaratnam, and Noah S. Diffenbaugh. “The extraordinary California drought of 2013/2014: Character, context, and the role of climate change.” Bulletin of the American Meteorological Society 95, no. 9 (2014): S3. http://forests4climate.org/wp-content/uploads/2014/10/Stanford-report.pdf

  [9] Stine, Scott. “Extreme and persistent drought in California and Patagonia during mediaeval time.” Nature 369, no. 6481 (1994): 546-549.

  [10] Fountain, Henry. “In California, a Wet Era May Be Ending.” New York Times, April 13, 2015. http://www.nytimes.com/2015/04/14/science/californias-history-of-drought-repeats.html

  [11] Harou, Julien J., Josué Medellín‐Azuara, Tingju Zhu, Stacy K. Tanaka, Jay R. Lund, Scott Stine, Marcelo A. Olivares, and Marion W. Jenkins. “Economic consequences of optimized water management for a prolonged, severe drought in California.” Water Resources Research 46, no. 5 (2010). https://watershed.ucdavis.edu/shed/lund/papers/HarouWRR2010.pdf

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