Low California Snowpack Raises Drought Concerns

Jan 5, 2018

From the looks of the “bathtub ring” around Lake Oroville, the vise of drought is quickly tightening around California’s neck. Fortunately, those looks are quite deceiving.

If you’ve had a gander recently at the largest state-owned reservoir in California, you’d might have a feeling of deja vu. It’s looking much like it did during the depths of the state’s recent drought.

A 300-foot swath of bare earth frames the receded water line. Houseboats and other water craft appear almost forlorn. Meanwhile, the clouds have proven quite fickle, with an abundant November followed by a stingy December.

The first monthly statewide snow survey, conducted earlier this week, revealed a sobering picture. Only 1.3 inches of snow was on the ground at Phillips Station, the water content just 3 percent of average.

Grant Davis is the director of the California Department of Water Resources.

“We’re obviously hopeful that we’ll have more snow the next time we come out here in the February, March and April snow melt surveys,” he said.

The all-important snow-water content figure stands at less than a tenth of where it was last year.

As the largest state-owned reservoir in California, and the linchpin of the State Water Project, it would seem that crisis is once again, just around the bend. But that’s not the case.

Doug Carlson is a spokesman for the California Department of Water Resources.

“Lake Oroville is the only reservoir in the state of California that’s being held below its historical average for this time of year,” Carlson said. “Oroville residents, Northern California people, they know why. It’s because of the spillway incidents we had last year, and we’re keeping it low to allow construction (that) went right into the winter months.”

And low it is. The reservoir was only 35 percent full as of the latest readings. That’s 56 percent of the historical average for this time of year. But zoom out a bit and the picture is much more comforting.

“The rest of the state has an abundance of water in the reservoir, thanks to last year’s record setting precipitation in Northern California, and very wet in the rest of the state,” Carlson said. “So, we’re not at all concerned about whether there’s enough water for California in the immediate months ahead.”

And he’s right. Every other major reservoir in California, both federally and state owned, has more water in it today than the average for this date in the historic records. Don Pedro Reservoir on the Tuolumne River is at 122 percent, New Melones on the Stansilaus is holding 143 percent, Trinity Lake is at 106 percent and the biggest one of them all, federally owned Shasta Lake, stands at 112 percent.

Even some of the water drained from Lake Oroville remains in storage.

“The water that goes into San Luis Reservoir is pumped from the California Aqueduct,” Carlson said. “And it’s currently at 117 percent of its historical Jan. 4th average. So, that’s where some of that water has gone that normally would have been held in Oroville.”

The other big number — the one most watched by growers — is the percentage of contracted water that will be delivered. Typically water managers initially announce very conservative amounts, figures that are gradually increased as the winter wears on and officials have a better picture of how much water they’ll have to divvy up. Carlson said they will deliver whatever is promised, even to growers north of the Delta. Right now, that figure is 15 percent.

“We do have other reservoirs north of the Delta of course, and the state and the federal government work cooperatively in managing the collective water resource in the state,” he said.

With a short and highly variable rainy season, much can change quickly. While typical Pacific storms, like the ones currently underway are more common, when California receives heavy and sustained rain and snow, it’s usually courtesy of “atmospheric river”-type storms. And like California winters generally, atmospheric river storm systems are fickle and hard to predict.

Michelle Mead is a warning coordination meteorologist with the National Weather Service’s Sacramento office.

“So far what we’re seeing is very typical for this time of year, so definitely keep track of the forecast, but it’s always in California’s history a good idea to conserve because we do vary so much from year to year,” Mead said. “From last year to this year is a perfect example of that.”