How is California’s landmark groundwater law impacting Sonoma County?

The drought is intensifying efforts to conserve all of Sonoma County’s water resources, including a supply that has eluded oversight until recently: groundwater. But even as plans for groundwater monitoring and sustainable use proceed, tensions are building over its management.

The authority to evaluate and regulate groundwater comes from a 2014 law crafted in the middle of the state’s last drought. It authorized government regulation for certain groundwater basins through the establishment of local agencies, with the goal of “sustainable” management – that is, no significant drop in groundwater tables year-to-year – by 2042.

Three of Sonoma County’s 14 groundwater basins are subject to such oversight: Sonoma Valley, the Santa Rosa Plain and Petaluma Valley. The location of these basins corresponds to both high population density and major groundwater demands.

“There are three levels of county stakeholders most affected by groundwater management,” said Ann DuBay, administrator for the Petaluma Valley and Sonoma Valley Groundwater Sustainability Agencies. “First are homeowners – mostly rural homeowners – who are on well water. Next is agriculture, which is a lynchpin of our economy. And finally, there’s the environment, including the streams and rivers that get at least some recharge from groundwater.”

Andy Rodgers, administrator for the Santa Rosa Plain agency, likens a groundwater basin to a subterranean bathtub: the volume of water the tub holds fluctuates depending on season and demand. Shallower basin aquifers may be connected to surface water such as streams, while deeper aquifers typically are not connected to surface flows.

Under the 2014 state law, the Sustainable Groundwater Management Act (SGMA), “local agencies are authorized for each medium to high priority basin, and a board and advisory committee are formed,” said Rodgers. “Once an agency is in place, the goal is the development of a groundwater plan that’s sustainable long-term.”

As an example, Rodgers cited the Santa Rosa Plain basin, which is now in a “slight water budget deficit.” Over time, said Rodgers, more water is extracted than replenished.

“During the next 20 years our job is to remove that budget deficit, or even achieve a net positive,” said Rodgers. “That’s the whole point of SGMA.”

The new drought is the first time California has had such regulation in place. And while the state law generally favors a soft approach that emphasizes groundwater quantification, monitoring and incentives for conservation, it isn’t toothless.

“We do have the authority to investigate, and if there are problems and clear lines of evidence, we do have the authority to take action,” said Rodgers.

Investigating ways to recharge local basins

Two of the county’s basins – the Santa Rosa Plain and the Petaluma Valley – are in relatively good shape, said DuBay.

“There has been recognition for some time that the Sonoma Valley has issues, specifically in deep aquifer declines,” said DuBay. “There are a couple of hot spots where this is particularly problematic – El Verano and the region around Eighth Street East come immediately to mind.”

Groundwater management is not wholly about monitoring and regulation – it’s also about replenishment, and the county is investigating several avenues for recharging local basins, said Jay Jasperse, the chief engineer and groundwater manager for Sonoma Water, the county agency.

“You get some profound benefits from recharging shallower aquifers that feed streams,” said Jasperse. “You enhance water supplies, of course, but you also get significant environmental benefits by maintaining stream flows.”

One approach to groundwater recharge is known by a wonky acronym: flood-MAR, short for Managed Aquifer Recharge. During high water river flows, water can be directed to nearby agricultural lands – vineyards along the Russian River are a good example. The standing water subsequently percolates down to underlying aquifers.

“Certain crops aren’t harmed by standing water, and research conducted in the Central Valley indicates (dormant) grapevines are in that category,” said Jasperse.

For deeper county aquifers, managers can direct Russian River winter flows through existing pipelines to established agricultural and municipal wells.

“We did a pilot study with a well in the Sonoma Valley, and it was successful,” Jasperse said. “Typically, there’s a SGMA process for implementing new data into the sustainability plans, but the drought is accelerating our responses in general. We’re looking to get one or more wells expedited for this approach in the near future.”

Deep-well injection a flashpoint

Rue Furch, an advisory committee member for the Santa Rosa Plain agency, said deep-well injection could be a worthwhile approach, “but it’s come up in the past, and it’s been a hot potato every time it’s been broached. No amount of research has been able to get past the political blowback.”

The region’s fractured geography is one underlying factor. The state law was designed for Central Valley groundwater basins, Furch said, where the consequences of severe overdraft — massive land subsidence — first became obvious.

“Central Valley groundwater basins are large and geologically simple,” Furch said. “Here our basins are complex, fractured by multiple faults. SGMA doesn’t take that into account. A better approach would be designating sustainability basins by watersheds — ridgeline to ridgeline. That would accommodate all the factors that can affect groundwater, including gravity.”

This disparity in county aquifers means groundwater availability can vary greatly even within discrete and designated basins, said Furch – and that can generate problems with no easy solution.

“Right now, the Board of Supervisors is initiating a study to determine if aquifer water could be used to supply some dairies in the south county that are in deep trouble,” she said, “but from one perspective that seems like robbing Peter to pay Paul. It’s a response that could lead to impacts elsewhere.”

Caitlin Cornwall, the senior project manager for the Sonoma Ecology Center and an advisory committee member for the Sonoma Valley groundwater agency, agreed with Furch that the state framework mostly applies to “flat valley bottoms, even though most of the water in Sonoma County falls — and much of it is retained — in the hills. SGMA provides no real mechanism for dealing with that.”

Agriculture dominates water use

Some rural well owners fear their interests are being ignored in favor of large agricultural interests. (Of the water used by people in California, agriculture accounts for about 80%.)

Sonoma County’s signature crop, wine grapes, cover about 65,000 acres and account for a dominant share of the water use, though even rough figures have long been hard to come by.

“My major question is, how much is agriculture using, and how much are they making off our water?” said Susan Bahl, the co-founder of the ad hoc group Rural Homeowners Alliance. “Why isn’t there a moratorium on wineries, new vineyard plantings and cannabis? Why aren’t growers going to dry-land viticulture, as you see in other areas?”

Rural homeowners, meanwhile, are doing their part for conservation — and more, said Bahl.

“I have a home garden and animals, but I keep my usage to 30 or 40 gallons a day,” she said. “Wineries and vineyards are not paying for their usage of our groundwater, and they have no limits on how much they can extract.”

Cornwall acknowledged growers and vintners are not currently facing restrictions on the amount of water they can pump, but said viticulture also is central to the county’s economy.

“It’s important that vineyards use water as efficiently as they can,” she said, “but it should also be noted that most areas in the world that grow unirrigated wine grapes also get some summer rain. So the comparison to Sonoma County isn’t exact. There’s a fine line to be walked between reducing the draw of our largest groundwater users and maintaining the viability of the county’s iconic industry.”

Mike Sangiacomo, a Sonoma Valley groundwater agency board member and a grower who cultivates about 1,500 acres of vineyard in Sonoma County, said farmers are doing more with less and less water, but many soil types can’t support unirrigated viticulture.

“There can be a significant difference between some water and no water,” said Sangiacomo. “Typically, you need at least a little water to keep both the vines and the soil healthy. And healthy vines and soil mean fewer inputs (such as agricultural chemicals).”

That said, Sangiacomo explained, he understands stakeholder angst, particularly in the Sonoma Valley where the groundwater situation is serious.

The local agency “is compiling all the data, and we’re all waiting for answers on groundwater quantification and availability,” he said. “People are a little nervous. As soon as you start considering regulation, everyone wants to make sure they get a fair shake.”

In the final analysis, groundwater regulation may conform to an assessment often applied to diplomacy: the art of the possible.

“I’m a pragmatist, and I believe in this process,” said Marlene Soiland, an advisory committee member representing rural well owners with the Santa Rosa Plain groundwater agency. “We have to find a way to make it equitable. I think of it as a Venn diagram, where we can all meet in the middle — the place where our interests intersect.”