Managing water supplies in the San Joaquin Valley in the coming years will require balancing supply with demand, addressing groundwater quality problems and finding new beneficial uses of land and water.
So asserts a team of researchers led by Ellen Hanak, Water Policy Center director and senior fellow at the Public Policy Institute of California.
The scientists note that the valley is ground zero for many of California’s most difficult water management problems, including groundwater overdraft, drinking water contamination and declines in habitat and native species.
In a paper titled “Water and the Future of the San Joaquin Valley,” they add that the Sustainable Groundwater Management Act (SGMA) will have a broad impact on valley agriculture and the regional economy in coming years and will likely include some permanent idling of farmland.
MUCH AT STAKE
“The San Joaquin Valley is at a pivotal moment,” Hanak said during a recent water workshop hosted by the Almond Board of California. “It’s the state’s largest economic region (geographically). Much is at stake for the economy, public health and the environment.”
The key will be to look for opportunities within the challenges, using “approaches that increase flexibility, provide incentives and leverage multiple benefits,” she told the gathering at the International Agri-Center in Tulare.
Hanak’s team, which included notable water and economic experts such as Thomas Harter and Jay Lund of the University of California, Davis, are the latest to demonstrate that the only way to bring the valley’s overburdened water supplies into balance will be to increase supply, mainly by making the most of available water, and reduce demand.
A sense of urgency has existed in the valley since SGMA was passed in 2014 at the height of the recent historic drought, as growers and regulators realize that the next drought is around the corner. As surface water was entirely shut off in some areas, many farms got by with groundwater. But the National Aeronautics and Space Administration reported in 2015 and again in 2017 that land in the valley is sinking at historic rates. Moreover, rigorous new state controls are being implemented to reduce nitrates and salinity in groundwater.
FINDING A BALANCE
Over the last 30 years, with a need of about 1.8 million acre-feet per year, there hasn’t been enough years of net groundwater recharge in the San Joaquin Valley, Hanak says.
Water users will have to “lower the bar” by using less so that net recharge is achieved in more years “so you can still draw down in very dry years,” she says.
The Almond Board and other organizations have invested heavily in projects to capture and store more local runoff in groundwater basins and reuse water, while larger infrastructure investments such as better conveyance of water from the Sacramento-San Joaquin River Delta have been suggested as long-term solutions.
Although farmers can save some water through crop choice and management, experts have been warning for several years that idling some farmland is likely in basins that can’t close the groundwater deficit with new supplies.
Groundwater sustainability agencies are considering a range of options, but they are not equally effective or practical, the scientists note.
“Supply options vary greatly in terms of the water that’s available as well as cost,” Hanak says. “Capturing water within the valley is the biggest thing. It’s in years like this when there’s a lot of extra water that makes its way out to the Golden Gate.”
Another problem created by perpetual overdraft is poor groundwater quality, which the researchers say impairs drinking water supplies in disadvantaged rural communities, reduces long-term agricultural prosperity, and degrades ecosystems.
In future years, landowners and agencies will need to manage water quantity and quality together “to take advantage of synergies and avoid unintended consequences,” the researchers write.
“Recharge projects will need to consider groundwater quality implications,” Hanak says. She notes that some almond orchards are on soils that are suitable for recharge, but landowners also have to consider the potential for leaching nitrates into the water table.
Coordination among agencies and growers will be challenging, the researchers say, because various programs addressing water quality are carried out by numerous local and regional entities, some of which have overlapping boundaries and responsibilities. But cooperation will be a key to the programs’ success, Hanak says.
“All of these solutions cannot be done farm by farm,” she says. “The state and federal government can help, but they can’t be the drivers.”
One potential solution to water shortages is groundwater marketing, which could reduce demand on pumping in overdrafted basins, contends Stacie Ann Silva, a resource analyst for the Fresno-based consulting service New Current Water and Land, LLC.
“They’re very different from surface water markets” in that they consist of individual transactions, Silva says. Each groundwater sustainability agency is handling these transactions differently, she says.
But markets encourage innovation, create value and recognize scarcity, says Bryce McAteer, executive director of the Eastern Tule Groundwater Sustainability Agency in Porterville. They are in use in Australia, among other places, he says.
“We’ve been mining our groundwater resources and we’ve seen the negative impacts from that,” he says.
As such, the ultimate solution for some growers will be to put farmland to other uses, Hanak and the other researchers assert. The resulting land-use changes in the San Joaquin Valley offer opportunities to put properties to good use while gaining “more pop per drop” from limited water resources, they write.
Land may be fallowed in places where excessive salt in soils has affected production, Hanak says. These lands could be used for solar panels, habitat restoration or groundwater recharge, she says.
For some growers, rotational fallowing may be more economically attractive than permanent land retirement. A system of idling segments of land a season at a time – usually with a cover crop – has been used by some farmers for decades as a way to boost soil health. Recent studies have shown the practice can improve soil moisture infiltration and retention and help with long-term productivity, the scientists note.
For high-value crops such as almonds that are known to use more water than some other crops, there’s been a big push to get “more crop per drop,” as Almond Board officials put it. They note that in the last 20 years, growers have reduced the amount of water it takes to grow a pound of almonds by 33 percent.
Richard Waycott, the Almond Board’s chief executive officer, compares hardships that will be caused by cutbacks in groundwater availability to other challenges the industry has faced, including salmonella outbreaks in 2001 and 2004 that prompted the industry to set up a mandatory pasteurization program.
In that crises as well as during the drought, the industry found a way forward, Waycott says.
“I sort of look at this in the same way,” he says.