Managing water and farmland transitions in the San Joaquin Valley

Implementation of the Sustainable Groundwater Management Act (SGMA) of 2014 will deliver long-term benefits to California’s agricultural communities, environment, and economy. This law directs local groundwater sustainability agencies (GSAs) to plan for and implement the transition to sustainable groundwater use—avoiding undesirable consequences of groundwater pumping and securing its future availability. Sustainably managing groundwater reserves is a critical hedge against climate change, which is leading to warmer and more severe droughts and increasingly erratic rainfall.

But implementing SGMA will have costs. The San Joaquin Valley, home to 4 million people and most of the overdraft areas in the state, is ground zero for tough decisions about SGMA. In two recent studies (Hanak et al. 2019, updated in Escriva-Bou et al. 2023), we have shown how a flexible approach to managing available water – by facilitating surface and groundwater circulation – can complement strategies to increase supplies. Together, these approaches can significantly reduce the costs of achieving sustainability. However, reducing water pumping by the valley’s largest water user – agriculture – will be unavoidable. In the most extreme scenario, nearly 900,000 of the valley’s 4.5 million acres of irrigated farmland could fall fallow to meet the necessary reductions in water use.

With nearly 20 percent of the San Joaquin Valley’s irrigated agricultural footprint at risk, it is critical to consider how to convert these lands to alternative productive uses that consume much less water. In more than seven years of conversations with various stakeholders in the valley—including water and land managers, farmers, researchers, representatives of local agencies, communities, and environmental organizations, among others—a recurring theme has emerged: a haphazard, unplanned fallow operation is widely viewed as a path to… Undesirable consequences for the valley’s economy, environment, and community well-being. Concerns include widespread land degradation due to weed infestations and loss of topsoil, setbacks to the valley’s progress on air quality, lost opportunities to create habitat connectivity, and increased risks of economic disruption in this densely populated agricultural region.

Progress in implementing SGMA. Implementation of SGMA has advanced significantly in the past few years. Under the law, public service agencies are responsible for submitting and implementing groundwater sustainability plans, and the state may intervene if it deems these plans insufficient. The plans must contain detailed estimates of water supply and demand, as well as projects and actions needed to balance the basins by the early 2040s while avoiding unwanted effects of pumping along the way.

Overall, the Valley’s geographic regions met deadlines for submitting their first global strategic plans – 2020 for the 11 highly cloudy basins and 2022 for the other four basins. But the review process was difficult. The California Department of Water Resources (DWR) has requested plan reviews in all 11 high-draft basins, citing inadequate coordination and a failure to adequately address undesirable outcomes, such as land subsidence and decreased drinking water reliability in rural communities. DWR approved the revised plans in four of these basins but deemed the revised plans inadequate in six other basins. (As of this writing, plans for the remaining five basins are still under review.) Basins that do not have adequate plans have been referred to the State Water Board, which will determine whether to designate the basins as test basins and directly supervise pumping (Department of State at California). Water Resources 2023, California State Water Resources Control Board 2023).

At the same time, the GSAs and their members began implementing their plans. Many plans emphasize water supply enhancement projects—particularly through groundwater recharge—and heavy rains in 2023 have stimulated significant new activity (Peterson and Barden 2023). Some government agencies directly address undesirable effects of pumping, for example, through programs to ensure drinking water supplies for local well users. Some have begun the difficult task of reducing groundwater use – by setting pumping allocations, incentivizing water users to pump less (for example, with extraction fees), launching local groundwater trades, and offering credits for fallow lands while following best practices. Administrative Soil Protection. .

Consider land use alternatives. In our recent work, we took a closer look at several land use alternatives that show promise for mitigating the negative aspects of large-scale land fallowing. For example, utility-scale solar development on former farmland is an attractive option that could help California achieve its clean energy goals, although it is limited by transmission capacity and permitting hurdles (Ayres et al. 2022). Another option involves keeping farmland in production with water-limited cropping systems such as winter forages (Peterson, Pitelko, and Landy 2022). Small doses of supplemental irrigation can allow farmers to establish these resilient crops across a wide area of ​​the valley and, with the right incentives, can help increase the resilience of agricultural operations. As lands shift away from intensively irrigated crop production, opportunities to restore valuable desert and upland habitats—and even some riparian and wetland areas—may also arise (Hanack, Peterson, and Hart 2022). Lands designated for expanding groundwater recharge can also serve as intermittent wetlands (Hanak et al. 2019). Finally, in a region that may continue to see significant population growth, new water-efficient development can help fill the groundwater gap while supporting local economies (Ayres et al. 2021a).

These synergies can help offset the costs of transitioning to groundwater sustainability. But there is more to it than just “what is the use of the land and where?” Adaptation measures – including water trading and land reuse – can address potential problems, but they may also cause unintended consequences. To ensure a balanced and beneficial transition to groundwater sustainability, fundamental changes will be needed to improve how institutions work together and design financial and regulatory programs to suit the new reality. It will be necessary to align incentives, coordinate policies and methods, and establish adequate sources of financing.

About this report. We begin by summarizing our findings on the scale of the valley’s water deficit, what this could mean for fallow lands, and how supply and demand management tools can help reduce the costs of water scarcity. We then delve deeper into how water trading impacts landscapes, and explore the potential opportunities and trade-offs of sharing water in this way. We’ve synthesized our findings on the promise and limitations of different alternatives for lands at risk of losing their water. Finally, we provide recommendations on how to manage water and agricultural land transitions in the most constructive way in order to secure a promising future for this important region. If successful, the San Joaquin Valley will provide valuable lessons for other agricultural regions in California and throughout the West that also face increasing water scarcity.

The Technical Appendix provides additional background on many of the analyzes presented here.

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