Storms Bring Drought Relief to California

The state hasn’t climbed out of the hole created by the five-year drought, but the snow and rain 2017 has seen so far have helped cut into the massive water deficit.
Storms Bring Drought Relief to California
These satellite images show the water level in Folsom Lake, the state's 11th-largest reservoir, in October 2015 compared to January 2017 following all the recent storm activity. (Courtesy of Planet Labs)

California’s drought isn’t fully in the past, but the state is beginning to bounce back. According to recent research from the University of Colorado-Boulder, California may have recouped 37 percent of the state’s five-year snow-water deficit because of the storms that have dumped on the Sierra Nevadas in the last month.

Researchers at the university’s Center for Water Earth Science and Technology used NASA satellite data to estimate that January snowstorms deposited about 17.5 million acre-feet of water on the Sierra Nevada range. That’s more than 120 percent of the range’s typical annual snow accumulation when comparing it to pre-drought averages.

On average, California’s snow-water deficit was about 10.8 million acre-feet per year during the drought years of 2012 through 2016, a total of 54 million acre-feet. So 17.5 million acre-feet in a month’s time eliminates a sizeable chunk of a years-long deficit. California counts on snowpack for about one-third of its water use.

“Early in the January storm cycle, lower mountain elevations received some rain, but the vast majority of the mountain precipitation has come as snow, which is exactly the way we need this precipitation,” says Thomas Painter, a snow scientist at NASA’s Jet Propulsion Laboratory, according to report on “As snow, it releases to reservoirs and ecosystems more gradually and efficiently over the summer months.”

The snowfall in the Sierra Nevadas coupled with consistent rain has brought much of the state out of an official “drought” designation. Just a few months ago, 80 percent of California was deemed a drought area by the federal government’s Drought Monitor. Now, only about half the state is in a drought, and all of it focused around the central and southern regions. Lake Cachuma, a major source of water for southern communities, is still at only 13 percent of its historical average. Northern California was declared drought free in mid January. That region has received 68 inches of rainfall this year, already exceeding the average annual amount of 50 inches.

But even in drought areas, the intensity has diminished considerably, with areas receiving more rain in January than they received during recent entire calendar years. According to the Drought Monitor’s weekly analysis, no part of California is in an “exceptional drought,” the most severe category, and only 2 percent of the state is in “extreme drought.” A year ago, 39 percent of the state had the “exceptional drought” classification.


But the massive amounts of precipitation in a short period of time have also had negative effects.

Take Lake Oroville, the state’s second-largest reservoir, and a common symbol of the effects of the drought in recent years, at one point plunging to 33 percent of capacity. Now it’s a symbol of the effects of the massive amount of snow and rain that have fallen in the last month.

Sunday, nearly 200,000 residents in the surrounding communities were ordered to evacuate when the Oroville Dam’s emergency spillway — in use for the first time in the dam’s 49-year history — was damaged due to erosion from the significant water flows, creating a flooding danger. The flow from the primary spillway was doubled, and by early Monday, the lake’s water level had dropped 3 feet, just enough to ward off catastrophe. Bill Croyle, acting director of the state’s Department of Water Resources, told the Washington Post that the lake would need to lower another 50 feet to reach normal operating levels for the system. With more rain in the forecast for later this week, officials are continuing to discharge as much water as possible without adding too much pressure to already damaged infrastructure.

“Our goal is to be able to use that infrastructure throughout this wet season,” Croyle says.


Still, the water use regulations that have become the norm in California are staying place for the time being. Recently, the State Water Resources Control Board extended the restrictions — which had been set to expire at the end of February — another 270 days despite some water suppliers calling for the governor’s emergency declaration of drought to be lifted.

“I believe allowing the regulation to expire is like making an airplane landing without deploying the landing gear. We’ll survive, but how will the airplane look?” Steven Moore, a board member, told the San Francisco Chronicle.

“Although this year may end up being wet, we can’t say whether it’s just going to be one wet year in another string of dry ones,” says Nancy Vogel, a spokesperson for the California Natural Resources Agency.

And while signs may be promising on the surface, with most major reservoirs above their historical averages and nearing their total capacity, underground aquifers still need plenty of replenishing.

“I’m a little reluctant to say the drought’s over, even though conditions have markedly improved,” Dan Cayan, a climate researcher at Scripps Institution of Oceanography, told KQED Science.

Farms and cities have drawn heavily on groundwater in recent years to make up for the dwindling surface water supplies, and Cayan says it could take several years of “bountiful water” to refill those underground aquifers.

“In the last 10 water years, eight have been dry, one wet, one average. Hopefully this year will end up being wet, but we cannot say whether it will be one wet year in another string of dry ones,” says state climatologist Mike Anderson.

For example, when the previous drought declaration ended in March 2011, it transitioned into one of the driest periods in California history.

The reliance on groundwater in recent years could have long-term effects. A report from NASA released last week showed areas of San Joaquin Valley continuing to experience significant subsidence — sinking land caused by excessive groundwater pumping that over time can permanently reduce an aquifer’s storage capacity. Two areas previously identified in 2015 had grown wider and deeper, and a new 7-mile area in Fresno County had settled 20 inches.

“Subsidence has long plagued certain regions of California, but the current rates jeopardize infrastructure serving millions of people,” Croyle says.

Subsidence has already caused sections of the California Aqueduct, which carries water from the Sierra Nevadas to the southern part of the state, to sink by more than 2 feet. That affects how flows have to be managed in those sections.

Sources: Washington PostSan Francisco ChronicleKQED Science;


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