By Peter Gleick, President
June 10, 2015
It’s only natural that during a crisis we look to single, “silver bullet” technical solutions, after all, they are supposed to be effective against werewolves, witches, and other monsters. For monsters like the ongoing severe California drought, the current favorite silver bullet is seawater desalination. And why not? California sits at the edge of the largest body of salt water in the world – the Pacific Ocean – and taking salt out of water is a successful, commercial, well-understood technology.
Look at how Israel has solved their water problems by building desalination plants, we’re told by The New York Times.
Look at how Australia responded to a massive multi-year drought by, in part, spending $10 billion to build six major desalination plants.
Look at recent statements from California Senator Barbara Boxer or from Senator Dianne Feinstein, saying they would push federal desalination efforts as a response to state’s drought.
Where does ocean desalination fit into the mix of water solutions for California? And what are the real lessons from Israeli and Australian experiences with desalination?
The real lesson is that desalination is a last resort, and even then, caution is warranted.
Israel didn’t turn to desalination until it radically transformed its agricultural sector to cut production of water-intensive crops like cotton and grains, invested in urban conservation and efficiency far beyond what California (despite its progress) has achieved, and massively expanded wastewater treatment and reuse. And Australia invested $10 billion in desalination plants, four of which they subsequently shut down or derated because they couldn’t afford to run them and didn’t need them.
Here are some important water numbers and facts:
Water Supply: Compared to Israel, California is water rich. California has an average total renewable water supply of over 2,300 cubic meters per person per year. Israel’s is around 230 – one-tenth as much. [One cubic meter is around 264 gallons.]
Wastewater: Israel currently treats and reuses 75% of its wastewater, compared to only 13% at present in California. California uses around 670,000 acre-feet of wastewater a year and throws away around 4.3 million acre-feet.
Water Use: Israel has pursued a very aggressive and effective water conservation program, far exceeding California’s. In Israel, current water use – including for municipal, industrial, and agricultural uses – is around 200 gallons per person per day (gpcd) (around 280 cubic meters per year), a 45% decrease from 1970. California’s water use is currently more than 1,000 gpcd (over 1,400 cubic meters per year), five times larger than Israel’s. Some of this can be attributed to conservation and efficiency, but it also reflects differences in the type and extent of agricultural and industrial development.
Agricultural Area: Between 1970 and 2011, Israel’s cultivated area dropped 30%. During the same period, California’s cropland expanded by 20%, increasing pressure on water resources (Israel’s Agriculture 2015, Olmstead 1997, USDA 2015). On average, Israel applies 1.6 acre-feet of water per acre of land; California farmers apply an average of 3 acre-feet per acre (Olmstead 1997, Israel’s Agriculture 2015, CDWR 2014).
The mix of crops in Israel has also shifted dramatically (see Figure 1), away from one dominated by water-intensive, low-valued field crops like cotton, barley, and wheat to one dominated by higher-valued fruits, nuts, and vegetables. California is also moving in this direction, but more slowly.
Irrigation Method: Over 80% of irrigated areas in Israel use micro-irrigation systems and the rest use precision sprinklers or mechanized systems like center pivots. In California, only 38% of irrigated land uses low-volume systems like drip, 15% use sprinklers, and the rest (around 46%) use flood/gravity/other systems (Israel’s Agriculture 2015, CDWR data).
Water Allocations and Rights: In Israel, water is regarded as a national asset protected by law. Users receive an annual quota from the Water Authority. The entire water supply is carefully measured and customers are charged according to their water consumption and the quality of the water used. Recycled water costs about half that of potable water (Israel’s Agriculture 2015).
California allocates water based on a century-old system of water rights; actual water use is not accurately measured or reported, including especially groundwater, and only some water prices are based on volume or quality.
Table 1 summarizes the key differences between Israel’s and California’s water availability and use.
Table 1. Water Comparisons: California and Israel
|Total Renewable Water Supply (cubic meters per person per year)||> 2,300||230|
|Total Water-Use per Person (cubic meters per person per year)||1,400||280|
|Wastewater Treatment (% of total wastewater)||13%||75%|
|Total Change in Harvested Agricultural Area (1960 to 2012)||+15%||-14%|
|Applied Agricultural Water (average), acre-feet per acre||3||1.6|
Sources: See full reference list below. Note that one cubic meter is 264 gallons.
Australia’s experience with desalination is equally sobering and enlightening. Australian residents are water misers compared to Californians. Average Australian households uses 54 gallons per person each day (for both indoor and outdoor uses), compared to 230 gallons in California; and in the state of Victoria, water usage is on only 40 gallons per person (Australian Bureau of Statistics 2013).
Australians lowered their water consumption dramatically over the past decade in response to the unprecedented Millennium Drought (2000-2010). Authorities responded by adopting new water-saving habits as well as water-efficient technologies. For example, dual-flush toilets are now found in nine out of ten Australian homes. A third of homes capture rooftop runoff in a rainwater tank, and the government offer rebates to residents installing rainwater tanks or graywater systems to recycle water (Heberger 2011).
Even with all of these efforts, desalination has been problematic: In response to the Millennium Drought they invested $10 billion dollars in desalination plants, most of which they now cannot afford to run. Four of the six major plants they built are shut down or running at a fraction of their capacity, but ratepayers are still paying for these plants. This is exactly what happened when Santa Barbara, California built an expensive desalination plant two decades ago and then had to mothball it because they couldn’t afford to run it and didn’t need the water because people conserved and there was cheaper water available. Yet that lesson seems to have been forgotten.
The bottom line for desalination in California? There is more desalination in California’s future. But the future isn’t here yet.
California should add desalination to the mix of options only after the state and local agencies do the other things that are more cost effective and environmentally appropriate first: continue to improve the efficiency of current water use, greatly expand wastewater treatment and reuse, and bring our agricultural economy into the 21st century. Even then, local agencies should think twice. There should be no subsidies or accelerated environmental review or special treatment to private companies seeking to build desalination plants and then sell the water under take-or-pay contracts to the public. Either desalination is the right choice or it isn’t. At the moment, in California, it isn’t.
Australian Bureau of Statistics. 2013. “Water,” chapter 2 in Information Paper: Towards the Australian Environmental-Economic Accounts, Canberra: Commonwealth of Australia.http://tinyurl.com/oa5eq4b
California Department of Water Resources (CDWR). 2014. Applied Water and Irrigated Acreage from the California Department of Water Resources. Statewide Water Balances, 1998–2010. Sacramento, California.
Cooley, H., PH Gleick, R. Wilkinson. 2014. Water Reuse Potential in California. Pacific Institute and NRDC. http://pacinst.org/wp-content/uploads/sites/21/2014/06/ca-water-reuse.pdf(Accessed June 8, 2015)
Heberger, M. 2011. “Australia’s Millennium Drought: Impacts and Responses,” in The World’s Water, Volume 7: The Biennial Report on Freshwater Resources, Peter H. Gleick, ed., 97-126. Washington, DC: Island Press.
Israel’s Agriculture. (Accessed 2015). http://www.moag.gov.il/agri/files/Israel%27s_Agriculture_Booklet.pdf. Accessed June 2015.
Olmstead, A. L. 1997. “The evolution of California agriculture.” Overview of the History of California. Retrieved: September 9, 2011. http://giannini.ucop.edu/CalAgBook/Chap1.pdf
United Nations Food and Agricultural Organization (FAO). 2015. AQUASTAT database. (Accessed on June 9, 2015.)
USDA, National Agricultural Statistics Service. Data accessed 2015. California data on harvested acreage in 2012 and crop production from USDA NASS.
Additional Pacific Institute Publications on Desalination
Desalination, With a Grain of Salt (Full report, 2006)
This blog was originally published in ScienceBlogs. You may find the original article here.