How ‘sustainable’ is California’s groundwater sustainability act?

Numerous issues around equity and the plan’s rollout loom.

Beneath the almond and citrus fields of the San Joaquin Valley lies an enormous system of aquifers that feeds some of the world’s most productive farmland. Hundreds of miles north and east, along the Nevada border, is the Surprise Valley, a remote, high-desert region undergirded by cone-shaped hollows of sediment that hold deposits of water. Both of these water systems, along with every other groundwater basin in California — a whopping 515 entities — must create individually tailored plans to manage their water use more sustainably. In scale and ambition, California’s Sustainable Groundwater Management Act (SGMA) has few parallels. And the work becomes increasingly urgent as the climate crisis makes water shortages increasingly severe.


Passed in 2014, SGMA is a complicated law that addresses what appears to be a straightforward problem: California doesn’t have enough groundwater. For decades, water users have taken out more than they put back in, with little statewide oversight. SGMA changes all that by drawing boundaries around the state’s groundwater basins (some, but not all, had been already defined and locally regulated) and requiring each one to create a local regulatory body and its own sustainability plan. These agencies must work with myriad stakeholders — public water systems, Indigenous nations, domestic and municipal well users and historically disadvantaged communities, as well as the ecosystems themselves.

Basins listed as critically overused had to submit plans to the state Department of Water Resources (DWR) by 2020. Those defined as high or medium priorities are submitting plans right now, with a deadline of Jan. 31, 2022. At that point, about 98% of the groundwater within SGMA’s purview — covering 25 million people — will have active plans. Each local entity has 20 years to prove that it is sustainably managing local groundwater.

SGMA is already having an impact. In Borrego Springs, a small town in Southern California, local stakeholders — including large agricultural water users, vacation resort owners and the area’s water district — recently agreed to cut pumped groundwater use by 74% by 2040, The Desert Sun reported. This is how SGMA is supposed to work, said Fran Pavley, a former chair of the Senate’s Natural Resources and Water Committee: Local agencies tailor plans to each basin’s hydrological specifics and quirks, but true agency lies with the local stakeholders. “That’s the brilliance of it,” Pavley said. “You come up with your own plan and you have to submit it. You have to do right by it, and if you don’t, the state will do it for you.”

This emphasis on local expertise points to SGMA’s possibilities — and its potential pitfalls — especially when it comes to deciding what “sustainable” water management means. Each management body has wide discretion to define “sustainability”  and the path to sustainability by 2040  for its particular basin. That’s not to say that SGMA doesn’t make demands: Each plan must include things like a list of water users, historic water conditions and future projections based on land use and climate models, as well as metrics for measuring success. SGMA also identifies undesirable outcomes, such as chronically low groundwater levels, poor water quality and impacts to connected systems of surface water. Melissa Rohde, a groundwater scientist with The Nature Conservancy, summed up the approach this way: “We’re not going to define sustainability, but we know what it isn’t.”

Freddy Medina takes apart irrigation piping on a farm in Helm, California, in preparation for the 2015 season. The farm is in a part of the San Joaquin Valley categorized as a critically overdrafted basin.

“We’re not going to define sustainability, but we know what it isn’t.”

This, according  to Rohde, makes it difficult to determine how the state will judge sustainability basin-by-basin. DWR, which is reviewing the available plans, has the authority to reject any it deems unlikely to achieve sustainability, though on what grounds remains unclear. None of its decisions are public yet. This approach has potentially serious impacts. Take, for example, an extensive study by the UC Davis Center for Regional Change that analyzed groundwater plans for nearly all the “critically over-drafted” basins submitted to the state in 2020. Thousands of small wells, the kind that serve households, are at risk of going dry because the lowest legally allowable depth for the top of the aquifer falls below where many domestic wells currently reach. And drilling deeper wells is expensive.

According to the study, this problem is especially acute in the San Joaquin Valley, the heart of California’s agricultural sector, which is a significant groundwater user. Many of the at-risk wells serve low-income and majority-Hispanic farmworker communities.

Then there’s the issue of SGMA’s breadth. The law actually leaves out quite a lot of water. It applies to “alluvial” basins — water stored in deposits of sediment, in other words. But it does not apply to brackish groundwater, which often sits below alluvial basins and can be treated and used. It also doesn’t govern water stored in fractured hard-rock and volcanic aquifers, since they are not alluvial basins. This a problem, because these forms of storage hold the majority of the state’s groundwater, and this leaves 40% of its wells unregulated and vulnerable to over-pumping, according to a study by The Nature Conservancy and Stanford University’s Water in the West Center. “Because SGMA says that it regulates ‘all groundwater basins in the state,’ most of the public reasonably assumes that the problem of groundwater management in California has been solved,” the study states. “Unfortunately, this is not the case.”

In 2015, an irrigation canal is dry downstream of the Friant Dam in a critically overdrafted basin.

Nick Bowlin is a correspondent at High Country News. Email him at [email protected] or submit a letter to the editor

Note: This story has been corrected. The groundwater study was released by UC Davis Center for Regional Change,  not the Pacific Institute.