You say California’s drought is over? Not so fast, water managers say

If California Gov. Gavin Newsom was looking for a dramatic way to illustrate the region’s dire conditions in the early days of the state’s latest, historic drought, he found it in the dry, deeply cracked reservoir bed of Lake Mendocino.

It was there, almost two years ago, that Newsom stood where there should have been 40 feet of water and proclaimed a local drought emergency for Sonoma and Mendocino counties, sounding an early alarm that would be amplified and echoed as the western drought spread across the state and deepened over the ensuing months.

The drought didn’t start that unseasonably warm April day, its sunny glare reflecting off the desiccated mud bed, nor at any particular moment.

It arrived over weeks and months when rain came in such paltry amounts the earth grew parched, and ponds and streams began to run dry.

Farmers already were trucking water at great expense to ranches and dairies that normally had their own supplies, and public reservoirs had reached record seasonal lows weeks before the governor invited the press to meet him on an expanse of chalky, scored mud in Mendocino County.

In the same way, the drought’s exit is a process, without a clear demarcation line or final pronouncement declaring the three-year drought over and done.

And despite lots of evidence to the contrary, local and state officials say we’re not there yet.

“It’s trending the right direction,” said Sonoma Water General Manager Grant Davis, whose agency provides wholesale water to contractors that supply more than 600,000 people in Sonoma and northern Marin counties. “But to say that it’s over, I don’t think you’ll find someone credible who could say that.”

After heavy winter rains in late December and January that oddly triggered wide flood evacuation warnings in the midst of an official “drought emergency,” local streams and creeks are running strongly now, ponds and reservoirs are brimful and the landscape has brightened to a brilliant green.

There’s also snow in the Mayacamas Mountains and the Russian River flowing higher than it has in four years.

Lake Sonoma’s water supply pool — the biggest bucket below a top layer for flood storage — is full for the first time since 2019, with enough volume to provide at least three years of drinking water for 600,000 North Bay residents.

Lake Mendocino, the region’s second largest reservoir, is taking on so much water through steady runoff the U.S. Army Corps of Engineers just increased water releases through Coyote Dam to make room for more rainfall predicted next week.

But don’t expect to see Newsom to stand against a frothing waterfall backdrop soon and proclaim the drought is done. State and local officials are in no great hurry to call the drought over.

Why not?

It has to do, experts say, with the layered, complex assessment of lasting impacts in such a deep drought — and its predecessors — and the differences between what’s happening with surface water supplies and those stored deep underground.

The ambiguity is likely confounding for many who saw news of the latest update Thursday out of the U.S. Drought Monitor.

The monitor’s weekly map, widely consulted for information about drought conditions across North America, showed all but about 11% of Sonoma County had emerged from drought over the previous week, along with the greater Bay Area, North Coast and inland Central Coast.

While those areas had been downgraded to “abnormally dry” conditions, much of the Central and South Coast, as well as the snow-encased Sierra, no longer even qualified as dry, according to the map.

Curtis Riganti, a climatologist with the National Drought Mitigation Center at the University of Nebraska-Lincoln, which produces the Drought Monitor in partnership with the U.S. Department of Agriculture and the National Oceanic and Atmospheric Administration, said the map is an attempt to reflect conditions in each area broadly.

It accounts for factors including precipitation, river flows, reservoir levels, soil moisture, snow pack, vegetation health, groundwater measures, evaporative demand and other data, as well as climate history.

“It’s kind of a holistic view of a bunch of different drought indices,” he said.

But it’s apparently not enough to persuade California officials to say the drought is over.

“It’s great to see improved conditions reflected in the U.S. Drought Monitor,” state Department of Water Resources Director Karla Nemeth said in an emailed statement.

“We continue to monitor conditions across California, and while recent rain and snow has been promising, it will take more than a single wet year for California to fully recover from the last three years — the driest ever recorded in state history. In the coming weeks, we’ll be assessing the impact the latest round of storms has had on the drought.”

Sonoma County and the North Coast are somewhat removed from many of the larger state considerations because the region’s water supply is not reliant on Sierra snowpack nor connected to the state water system or any of its massive reservoirs.

Most urban residents and agricultural users along the river depend on water from the Russian River watershed. It captures water from a 1,485-square-mile area around Lake Mendocino, east of Ukiah, to Lake Sonoma, at the head of Dry Creek in Sonoma County.

Lake Mendocino also is supplemented by Eel River water from Lake Pillsbury in Lake County.

But as those surface supplies for cities, rural residents and farms ran low during the driest periods in the past three years, groundwater across the region was tapped more heavily. And those aquifers take longer to recover than surface water, experts say.

“People just see that Lake Sonoma and Lake Mendocino are at capacity and the Russian River is flowing really nice, but you need to look at the rest of the Santa Rosa Plain,” said Jeffrey DuVall, deputy emergency management director for Sonoma County. “What is under there? Are we seeing those aquifers and those other places that aren’t on the Russian River or close to the river fill back up with water underneath?”

There’s also persistent ecological damage, including the demise of millions of trees in California’s drought-stressed forests and the near collapse of chinook salmon stocks, according to recent federal fisheries forecasts.

Recent history also tells meteorologists and water managers how extreme and unpredictable weather patterns have become: The return of rain after a long dry spell can just as easily reverse.

Nick Malasavage, chief of operations and readiness for the U.S. Army Corps of Engineers’ Golden Gate District, which manages flood control operations at lakes Sonoma and Mendocino, used a financial analogy to explain.

Cash in hand — stored water for the short term — doesn’t automatically represent a stable, long-term supply, especially if your assumptions about normal conditions are unreliable.

“Surface water security and water supply security for now and this year, we’ll say, is plentiful in the moment and the season,” Malasavage said. “But that doesn’t really buy back for that protracted and multiyear period without water security.”

Said DuVall: “Everything we don’t see above ground — those aquifers and everything — still need time to recharge.”

The Sonoma County Board of Supervisors, in fact, is scheduled April 4 to consider renewing the drought emergency proclamation it first approved April 27, 2021, and has extended for 60 days at a time since.

The proclamation enhances eligibility for grants and government help with contingency planning and addressing water shortages, as well as emergency, drought-related repairs to infrastructure, DuVall said. It also affords opportunity to pursue projects on an emergency basis, he said.

Water officials and emergency managers on the county drought task force had spent months preparing for a fourth dry winter before the rain came heavy in late December.

The past decade shows why there is reason for caution and additional conservation, DuVall signaled. It featured two severe multiyear droughts separated by just a couple of years of somewhat average rainfall.

And that’s against a larger backdrop of climate change and long-term aridification of the parts of the western states, that work still needs to continue, DuVall said.

It seems, he said, “this is our new cycle: drought, rain, drought, rain, drought, rain.”

You can reach Staff Writer Mary Callahan (she/her) at 707-521-5249 or mary.callahan@pressdemocrat.com. On Twitter @MaryCallahan.