Jan 22, 2017

A Wet Year Won’t Beat California’s Never-Ending Drought

Forestville, CA
USA
by
Peter Gleick
,
Wired
A flooded vineyard in the Russian River valley in Forestville, California, on January 9, 2017. Photo: Eric Risberg, AP
A flooded vineyard in the Russian River valley in Forestville, California, on January 9, 2017. Photo: Eric Risberg, AP

STORM AFTER STORM has pummeled California over the past few weeks as a series of so-called atmospheric rivers has come ashore. Given the massive amounts of rain and snow that have fallen, people want to know if California’s five-year-long intensive drought is finally over.

The answer, of course, depends on what people mean by “drought” and “over,” and it depends on who you ask. There isn’t—and never has been—agreement about the meaning of either word.

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Common drought indicators evaluate the balance between the water that comes into the state, via rain and snow, and the water that goes out in runoff, consumption, and evaporation. By any measure, California’s five-year drought, from 2012 to 2016, was extreme. Indeed, precipitation, runoff, and soil moisture in the Sacramento and San Joaquin river basins have been far below normal for a long time.

So far, this water year, which began October 1, is different. The chances are excellent that rain, snow, and runoff will be far above average. At this point in January, Northern California has already received almost its entire annual average precipitation, the snowpack is at 150 percent of normal, and reservoirs are filling up. The abundance of rain and snow so far this year led the National Drought Mitigation Center to conclude that the drought in northern California is over.

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But another key variable is temperature. Temperature determines, among other things, the demand for water by crops, vegetation, and people, and especially the ratio of snow to rain that falls in the mountains. The past five years were by far the driest and hottest in more than a century of recordkeeping—in part because of human-caused climate change—and those high temperatures played a key role in worsening the scarcity of water and devastating the snowpack. This combination of hot and dry led to massive groundwater overdraft, cutbacks to farmers, loss of snow storage in the mountains, reductions in hydropower production, and a range of voluntary and mandatory restrictions on urban water use. And while the wet year may end the “precipitation drought,” higher and higher temperatures and a persistent “snow drought” are here to stay.

Worst of all, these hydrological and meteorological measures don’t tell the whole story. Even in a wet year in California, nature’s bounty of water is no longer enough to satisfy all the state’s demands, recharge overdrafted groundwater basins in the San Joaquin valley, or overcome the massive deficits suffered by California’s ecosystems and endangered fisheries. Far more water has been claimed on paper than can ever be reliably and consistently delivered to users. If the most straightforward definition of drought is the simple mismatch between the amounts of water nature provides and the amounts of water that humans and the environment demand, California is in a permanent drought.

Whether or not the drought is officially declared “over” and emergency restrictions are lifted, we must still face up to the fact that our water system is out of balance, even in a wet year. Demands exceed supply, disadvantaged communities don’t have reliable access to safe water, ecosystems are dying, and our water systems are unsustainable and poorly managed. And in the context of a changing climate, these problems will only worsen.