‘Not a drought buster.’ Northern California rainstorm will help but not end water woes

The rainstorm pelting Sacramento and Northern California will help remedy the state’s woeful water situation.

But it won’t be nearly enough to end the epic California drought.

“Even with 5 inches of rain in Sacramento, our deficits are immense,” said Jeffrey Mount, a geologist and water expert at the Public Policy Institute of California. “We’re basically missing two years of ‘precip’ in this basin.

“It’s not a drought buster.”

The main problem is that the drought, coupled with climate change, has dried out the soils of Northern California — meaning that much of the rain and snow will simply disappear into the ground.

“The soil moisture throughout Northern California has been depleted the last couple of years,” said Jay Lund, co-director of the Center for Watershed Sciences at UC Davis. “You need to soak the soil first.”

That issue became obvious last spring. A second straight dry winter left the state in bad but not terrible shape, with the Sierra Nevada snowpack at about 40% below average. Then most of that snowpack vanished, with some evaporating and much of it seeping into the dry soil instead of flowing into the reservoirs. Roughly 800,000 acre-feet of water — nearly enough to fill Folsom Lake, one of the state’s most important reservoirs — was gone.

In a matter of weeks, the drought had become disastrous.

But if the current storm won’t fix everything, it will set the stage for later storms, which will generate the runoff California desperately needs.

“Early season storms like this are great,” Mount said. “They wet the soils. They fill up the sponge.”

That said, the rain was coming down so hard Sunday that it would likely generate at least some runoff in the near term — sparking fears of flash floods in areas stripped bare of vegetation by the Caldor, Dixie and other wildfires, but also bringing some of the state’s reservoirs partially back to life.

Based on the projected flows on the American River, as much as 80,000 acre-feet could pour into Folsom Lake in the coming days, Mount said. An acre-foot is 326,000 gallons.

“We will see Folsom rise,” he said. Folsom is just 22% full, less than half what it should be for this time of year.

And already the wet weather is creating some immediate relief in other parts of the state. The State Water Resources Control Board on Thursday temporarily lifted the emergency curtailment orders that had prevented North Coast cities and farms from taking water out of the Russian River watershed — one of the hardest-hit areas of the state. The order is scheduled to go back into effect Nov. 1.

Lund said the decision in Sonoma County and points along the North Coast reflects the relatively small size of the Russian watershed, which can respond fairly quickly to a burst of rain.

It also makes sense because, at a time when many Californians have yet to embrace Gov. Gavin Newsom’s call for a 15% reduction in water consumption, “it’s important to maintain credibility,” Mount said. In August, water usage fell only 5%, the state said.

At the same time, Newsom made clear the drought isn’t going away soon. Last week he signed an executive order extending the drought emergency to the entire state, including areas such as Southern California that had been in relatively good shape.

The order also lets the state water board ban “wasteful water practices, including the use of potable water for washing sidewalks and driveways,” Newsom’s office said.