OpenET uses data from a constellation of satellites. (Illustration: NASA)

By Scott Hamilton, President, Hamilton Resources Economics

In July of 2020, the Governor released his Water Resilience Portfolio. It is the Administration’s blueprint for equipping California to cope with more extreme droughts and floods, rising temperatures, declining fish populations, over-reliance on unsustainable groundwater, and other challenges. Its four main objectives are to maintain and diversify water supplies, protect and enhance ecosystems, build connections, and become prepared for droughts, climate change, and natural disasters. These are sound fundamentals but the plan lacked substance. The Resilience Portfolio was followed in August of 2022 with a water supply strategy intended to ensure that California has the water needed for generations to come. It proposed initiatives to increase supplies over time—1.6 million acre-feet by 2030 and 2.9 million acre-feet by 2040. Those objectives are to be achieved through a combination of recycling, desalination, increased conservation, and increased stormwater capture. Nearly all of that supply is targeted at urban areas. And given that the Valley’s shortages alone are estimated to be 3 million acre-feet, the plan is still well short of where it needs to be.

Drought hit Sacramento Valley and North Coast agriculture hardest as a share of crop revenues. (Graphic: Medellín-Azuara et al. (2022), Adapted)

Against that background, the Valley Strong Energy Institute and the Kern Community College District hosted a webinar on September 13th titled “Water Policy in the San Joaquin Valley: New Tools and Solutions” presenting a panel of three speakers: Alvar Escriva-Bou, a senior fellow with the Public Policy Institute of California (PPIC), Thomas Ott from the Desert Research Institute, and Josué Medellín-Azuara, an Associate Professor in Environmental Engineering at UC Merced. 

Around 1,000 domestic wells were reported dry during 2021, most of them in the Central Valley. (Graphic: Escriva-Bou et al. 2022, Data: DWR)

PPIC has a good reputation for producing sound work, especially when it comes to gathering and presenting the information. Escriva-Bou summarized some of DWRs’ main concerns with Groundwater Sustainability Plans: they tended not to adequately address the impacts of subsidence and the impacts of overdraft on drinking water wells; some plans don’t coordinate adequately on data methods and management approaches; some plans don’t propose enough actions to close the supply-demand imbalance. These issues have largely been addressed in revised Groundwater Sustainability Plans recently resubmitted to DWR. Additionally, PPIC thought some plans underestimated the overdraft and were overly optimistic about the potential for new supplies while placing too little emphasis on demand management. PPIC’s proposed priorities for state support are heavily demand-oriented—a strategy likely to have severe economic and social consequences for the Valley. They suggest that those consequences can be mitigated through more active water markets, but current state law prohibits the transfer of water outside of a water district unless the water is surplus to the needs of the district. Under SGMA, that is now a high hurdle and so the mitigating effects of water transfers are likely to be minimal. 

Thomas Ott updated the audience on the recent developments of using satellite imagery to estimate crop consumptive use, particularly the “OpenET” tool—a source of valuable information for groundwater managers and farmers. The tool was developed as part of a collaborative effort between USDA, USGS, Google Earth, the Desert Research Institute, and several universities. The tool uses several different models—with the accuracy of the models varying with crop and soil conditions. Generally, the satellite estimates were within 10 percent of estimates provided by flux towers (weather stations) in the field. Ott noted though that citrus and almond growers in Kern County had some concerns with the estimates being provided, which will require additional model calibration to correct. 

Josué Medellín-Azuara ended the presentations by providing an overview of the drought impacts in 2021. Surface water supply shortages to agriculture were about 5.5 million acre-feet in 2021, offset by 4.2 million acre-feet of groundwater pumping resulting in net water losses of 1.34 million acre-feet. Idling of rice fields in Sacramento valley, cotton in the San Joaquin Valley, and other row crops represented the most losses in acreage. Drought-related idling of land was at least 385,000 acres in the Central Valley with the bulk of it in the Sacramento Valley during 2021. The preliminary direct economic impact of the 2021 drought on crop agriculture in the study area is estimated at $962 million worth 8,745 full and part-time job losses and $610 million losses in value added. Medellín-Azuara’s look ahead contained numerous words of caution: expect extremes in climate to continue, expect water shortages to increase with the implementation of SGMA, and consider alternative crop mixes—combinations of row and permanent crops—to better manage variations in the water supply.

The economic and social impacts due to the drought this year and last are likely a sign of things to come as drought impacts are replaced by those due to the implementation of SGMA. While demand management and repurposing of ag land will necessarily be a part of the solution, it should be the last option, not the first. As the signs along Highway 99 suggest, there is a need to make better use of the 10 million acre-feet per year, on average, that flow to the Pacific from the Delta that is not needed for any other purpose. 

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