As Arizona farmers and ranchers face the worst water crisis in state history, a new report from the University of Arizona Southwest Center suggests that a variety of new farming practices, water policies and increased access to information could help the agricultural industry remain prosperous and help sustain the river ecosystem in the Lower Colorado River Basin.

The report, "Toward Water-Resilient Agriculture in Arizona: Future Scenarios Addressing Water Scarcity in the Lower Colorado River Basin," was commissioned by the Lincoln Institute's Babbitt Center for Land and Water Policy and was written by university researchers and collaborators from the Arizona-Sonora Desert Museum and Sustainable Waters, a global water education service.

"This agricultural water crisis is arguably the worst in the Colorado River watershed since Arizona statehood, more than a century ago," said Gary Nabhan, a research social scientist at the Southwest Center and the Kellogg Endowed Chair in Southwestern Borderlands Food and Water Security. "It is important for the university to find and implement solutions that not only help Arizona farmers, but also assist all others who may soon be impacted by scarce resources and higher prices."  

According to the report, the Colorado River's natural sources of replenishment – snowmelt and rain – have been 20% lower in recent decades than the 20th century average, a change attributed to the ongoing severe drought affecting the West, exacerbated by warming temperatures. Even as the river is gaining less water, society's use of the river has not decreased. As a result, for 18 of the last 23 years, urban and agricultural water needs exceeded the rate at which the river can replenish. As a major source of water, the Colorado River feeds the two largest storage reservoirs in the nation: Lake Powell and Lake Mead. At the end of the 20th century, both were nearly full. The two lakes closed out 2022 roughly three-quarters empty.

Through the Bureau of Reclamation, the U.S. Department of the Interior is closely involved in managing the water supply of the Colorado River Basin, which includes regulating the amount of water Arizona receives. Water rationing mandated by the federal government at the beginning of 2023 reduced Arizona's allocation from the Colorado River by 592,000-acre-feet, a 21% reduction in supply. That reduction is on top of the 18%, or 512,000-acre-feet, cut in 2022.

While all water users may notice changes like higher water bills, reductions primarily impact private and tribal farms in Pinal, Maricopa and Pima counties dependent on surface water for irrigation. According to report co-author and Sustainable Waters President Brian Richter, irrigated farms most severely impacted by water cuts already dealt with an 87% reduction in total surface water allotments in 2022. This year, some Pinal County farmers will receive just 5% of their 2021 water allotment from the river.

Nabhan said that changes in water policy have forced farmers to look toward increased groundwater pumping to meet irrigation needs, even though aquifers are already being depleted and pumping is costly. Declining aquifers, combined with rising temperatures, increased salinization of soil, and water loss through evaporation and transpiration, add even more stress to the water scarcity dilemma for Arizona farmers – even if they don't rely on surface water.

"These changes are making it increasingly difficult to grow the same crops or use the same irrigation practices that farmers across the desert Southwest have relied on for more than 100 years," said report co-author Erin Riordan, a research associate with the university's Arizona Institute for Resilience and a conservation research scientist at the Arizona-Sonora Desert Museum.

Navigating shallow waters

To start a conversation about potential adaptations in the face of the growing water crisis, the Southwest Center sent out a 100-question survey in August to farmers, ranchers, water policy experts, agroecologists, food systems analysts and other experts. The following month, the center hosted a retreat with stakeholders at Biosphere2. During the retreat, participants brainstormed solutions that could benefit the agriculture industry and its consumers while balancing environmental water needs.

Multidisciplinary teams at the retreat developed possible strategies for water-resilient agriculture, identified factors that could help or hurt adoption of those strategies, suggested case studies of on-farm climate adaptation, and identified gaps in knowledge. The group also identified three key issues for legislators, tribal and water experts, and the agricultural industry to address: water certainty in the Colorado River Basin, holistic agriculture and watershed management, and restoring value to abandoned farmland.

Possible solutions that address those key issues are as wide-ranging as the issues themselves and include developing a market for reallocating water among agricultural users; growing more climate-appropriate crops and native plants; and developing shaded areas or using solar panels to provide shade for agriculture. Possible solutions included in the report could be implemented at the scale of a single field, an entire farm or rural community, watershed or the entire Colorado River Basin.

"We hope to demonstrate that there are already potential solutions at hand that will help farmers cut input costs while garnering better prices for their harvests," Nabhan said.

The report also highlights sources of technical, legal and financial support available to help farmers adapt to an ever-changing climate, as well as to shifts in water and energy availability in Arizona.

The report is among several UArizona initiatives intended to support Arizona farmers.

The university and three nonprofit organizations received a $4.7 million grant from the U.S. Department of Agriculture late last year to form the Arizona Partnership for Climate-Smart Food Crops, a three-year project that will help farmers throughout the state more rapidly implement climate-friendly solutions that reduce costs while promoting value-added products in the economy.

UArizona President Robert C. Robbins also announced the formation of the Presidential Advisory Commission on the Future of Agriculture and Food Production in a Drying Climate, a group charged with suggesting actions to bring the resources of the university to bear on keeping agriculture productive even in the face of less water.

Nabhan said the agricultural industry needs to invest in a transition to water- and fuel-efficient practices that serve as economically viable adaptations to longer-term water scarcity, "and not just in Band-Aid remedies that don't move the needle."

"If we can stabilize or increase crop value per acre while cutting water and energy costs, everyone stands to gain over the long haul," he said.