California’s recent water windfall is a bit like somebody getting a big tax refund after years of dipping into their 401(k) to pay the bills. Any sense of wealth this sudden bounty engenders will be fleeting and perhaps dangerously misleading.
Weeks of heavy snow and rainstorms, poetically known as atmospheric rivers, have essentially ended the state’s three-year drought. Just 9% of California is still experiencing “severe drought” conditions, down from almost 33% a month ago, according to the National Oceanic and Atmospheric Administration. Some of the state’s formerly parched reservoirs are overflowing.
But the deluge on the surface has barely replenished the state’s groundwater, the 401(k) on which this and future generations of Californians will depend. Decades of mismanagement and below-average rainfall have led farmers, homeowners and businesses to drain it. With a heating planet making extreme weather such as droughts and floods more likely, it would be a grave error to think a few months of precipitation will let the state off the hook for shoring up this critical resource.
“In California we don’t do the basics to manage droughts,” says Michael Kiparsky, director of the Wheeler Water Institute at the University of California, Berkeley, School of Law. “If we declare victory just because it rained, then we lose the opportunity to prepare now for the next drought.”
Measuring California’s groundwater capacity with precision is difficult, but it could hold an estimated 800 million to 1.3 billion acre-feet of water. An acre-foot is a measure of how much water it takes to submerge an acre of land, or roughly one American football field, in a foot of water. In contrast, all of California’s surface reservoirs combined hold just 50 million acre-feet of water when filled to the brim.
California’s Department of Water Resources periodically takes readings from thousands of wells in an effort to plumb these depths. In its latest survey, it found water levels in 51% of wells had retreated by five feet or more over the past five years. Levels had dropped by more than 25 feet in 14% of the wells. Nearly 1,500 wells went dry last year, the most since the agency started keeping track in 2013, and likely an undercount.
A recent study by the University of Saskatchewan’s Global Institute for Water Security found that groundwater in California’s Central Valley had shrunk by about 36 million acre-feet since 2003, equivalent to the disappearance of Lake Mead, the biggest surface reservoir in the U.S.
The other hint that groundwater is in serious decline is the fact that, in much of the Central Valley, the ground is sinking so much that it can be studied from space. In parts of the Tulare Lake region — site of a former freshwater lake bled dry by farms and cities — the ground has sunk by more than 1 foot per year for the past five years, according to the water resources agency.
When there isn’t enough snow and rain to keep surface reservoirs filled, users have to tap groundwater. And the past 22 years have been California’s driest stretch since roughly the year 800, a recent study estimated.
This winter’s deluges will go a little way toward making up lost ground. But there is no guarantee wet conditions will continue. The first few months of 2022 put the state on pace for a record year of precipitation. (1) Then the atmospheric rivers disappeared, and the year ended with 20% less precipitation than usual, putting even more strain on groundwater.
“It will take several years, or even decades, of normal or above-average conditions, combined with appropriate management actions, to counter the decades of depletion of our groundwater resources,” the Department of Water Resources wrote in its latest groundwater report.
The possible return of the El Niño weather pattern in the Pacific after three years of La Niña conditions does offer some reason to hope. On average, El Niño makes California wetter. But that’s no sure thing. A strong El Niño in 2015-16 couldn’t reverse the long-term trend of declining precipitation and shrinking groundwater.
So California, like many places, will need to do a better job of saving its water windfalls. This is partly an engineering problem. The state’s Safe Clean Water Act of 2018 throws $280 million in tax dollars per year at the problem of funneling floodwater into the ground. The results so far have been disappointing, suggested a recent report by Los Angeles Waterkeeper, a nonprofit group.
But better groundwater replenishment would only address the supply side of the water equation. Reducing demand is even more important. Unfortunately, that is a knottier, political problem. Berkeley’s Kiparsky points out the state Water Resources Control Board — the referee ostensibly in charge of doling out water rights — lacks the resources, funding and authority to properly do its job.
Unlike other Western states, which use an established pecking order to determine which water users must give up some or all of their rights to increasingly scarce water each year, California’s approach is more ad hoc, and less effective. Even in the depths of the latest drought, as hundreds of wells were running dry, farmers in the Central Valley were still drilling new ones.
It will take political will on the part of Governor Gavin Newsom and California’s legislature to make the tough calls needed to shore up the state’s most important asset for the future. After decades of drought, you would hope that will is strong enough to withstand a few buckets of cold water.
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(1) We’re talking here about “water years,” which, like many fiscal years, run from October to September.
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ABOUT THE WRITER
Mark Gongloff is a Bloomberg Opinion editor and columnist covering climate change. A former managing editor of Fortune.com, he ran the HuffPost’s business and technology coverage and was a reporter and editor for the Wall Street Journal.
This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.