California regulators tell Sacramento Valley groundwater agencies to fix sustainability plans

California regulators have told local agencies in western portions of the Sacramento Valley that their plans to combat groundwater overpumping need fixing, giving them six months to revise their plans before the state agency makes a final determination.

The Department of Water Resources said Thursday that officials determined that local groundwater plans are incomplete in areas of the Sacramento Valley where prolonged drought and heavy agricultural pumping drew down aquifers and left residential wells dry.

So-called groundwater sustainability plans are required under California’s 2014 Sustainable Groundwater Management Act, which aims to tackle the state’s widespread groundwater depletion problem by 2040.

This step marks the first of two approval opportunities for Sacramento Valley agencies. Groundwater sustainability plans deemed incomplete include Colusa, Corning, Antelope, Los Molinos and Red Bluff — located in the west and northern reaches of the valley.

Paul Gosselin, deputy director of the Department of Water Resources’ sustainable groundwater management office, said their plans need more rigorous strategies to combat subsidence, groundwater overdraft and dry domestic and agricultural wells.

“For each one of these basins that were incomplete, there were one or two deficiencies or missing key pieces,” Gosselin said. “We’re looking forward to working with them and helping guide amendments to their plans to keep them on track for sustainability.”

The department also approved groundwater sustainability plans this week for several Sacramento area agencies, including in the Consumnes, Eel River Valley, Sutter and Yolo groundwater basins.

“Obviously, it’s disappointing to get back an incomplete, but our goal is to provide a long term sustainability plan,” said Justin Jenson, Tehama county deputy director of public works and Red Bluff groundwater sustainability agency executive.

To get the plan into shape, Jenson said the agency plans to work with DWR staff and consultants over the next couple months to gather additional info on preventing basin overdraft and setting minimum aquifer levels.

“We want to have a compliant plan and move forward, and avoid state intervention of any type. Because local control in situations like this often turns out to be the lowest cost for the community.”

In the San Joaquin Valley, home to some of the region’s most severely overdrafted groundwater basins, several plans have been rejected as inadequate under the law, which allows state regulators to step in and require stronger groundwater pumping rules.

Groundwater levels have declined across the Central Valley over the last several years of severe drought as river supplies dwindled and the agriculture industry relied more heavily on groundwater pumped from wells. Even as this year brought record-breaking snow and rain, plus recharge opportunities, aquifers will take years to replenish.

Dry wells and subsidence, when shrinking groundwater tables causes land to sink, have been historically minimal in the Sacramento Valley. The region is better known for its reliable surface water supplies from the Sierra Nevada snowpack and Sacramento river.

But a recent period of climate extremes threw those conditions into question, forging a new reality for the region that regulators are now calling on local agencies to address in more substantive sustainability plans.

Extremely dry years in 2021 and 2022 coupled with a historic drought from 2011 to 2017 wrought a severe toll on the region’s cropland, which depends on both surface and groundwater. In 2022, farmers pumped more groundwater to make up the difference.

The drought spurred a $1.3 billion loss in economic value in the region and more than 370,000 acres of farmland were fallowed, according to a UC Davis study. Hundreds of wells were reported dry and signs of subsidence began.

Last year, DWR reported more than .1 feet of subsidence in about 270 miles of the Sacramento River Region. The impacts were especially concentrated in areas with less dependable surface water accessibility; many of the dry wells were reported in areas such as Corning, Anderson and Red Bluff.

“I’m not surprised that they’re focusing on the Northern Sac Valley right now, because it was hit so hard by the last drought,” said Ellen Hanak, chair of water policy at the Public Policy Institute of California, of DWR’s action.

“The region has a lot of surface water, but with surface water there are haves and have nots. So you have both communities and some agriculture that are heavily dependent on groundwater all the time.”

Sacramento Valley aquifers are in a far better condition now, thanks to last year’s record storms and snowpack. Groundwater recharge is also increasingly seen as a key part of the solution to managing oscillating periods of extreme dry and wet.

DWR estimated that some 3.8 million acre-feet of water was put back into aquifers in 2023. That replenishment can help fend off encroaching subsidence and put water away for future dry years. But long term issues remain.

“DWR deeming these plans incomplete is a signal that we need to solve the subsidence problem, and I also think they weren’t comfortable with the methodologies they used,” said David Guy, president of the Northern California Water Association, which works with local agencies across the Sacramento Valley.

“They’re learning, and I think there are some things that they didn’t get right in the eyes of DWR. But they have an opportunity here to help cure that and I think they’ll be able to.”