SDSU: The shape of Imperial Valley water

Irrigation canal in the Imperial-Mexicali Valley/Biggs Watershed Science Lab

SDSU researchers examine the effects of shrinking water supplies in the Imperial-Mexicali Valley.

Whenever it rained, six-year-old Trent Biggs would get in trouble for digging ditches in the school playground. “I just liked watching water flow around,” he explained.

He still does. Now a San Diego State University geography professor, Biggs leads water-use studies from the Himalayan foothills of Nepal to the Amazon rainforests of Brazil. Closer to home, he’s focused on the Sonoran desert towns and farms that surround SDSU’s Imperial Valley campus on both sides of the U.S.-Mexico border.

The problems there are as old as the urbanization of Southern California: insufficient water to meet community demands and ecosystem needs. The solutions, which could figure into future policy-making, are both increasingly high-tech and surprisingly personal.

“All the big environmental issues come together around water, and Imperial-Mexicali Valley is a great place to study all those issues because it incorporates them in one place,” Biggs said.

The Biggs Watershed Science Lab’s work in Imperial Valley is a collaborative effort, comprising multiple studies by faculty and students from both campuses. They are joined by research colleagues in the Imperial Valley at the Cooperative Extension Office of the University of California, Davis and the Imperial Irrigation District; by the nonprofits Pacific Institute and Comite de la Valle; and by researchers across the border at the Universidad Autónoma de Baja California and El Colegio de la Frontera Norte.

Together, these groups aim to assess the effects of shrinking water supplies in an arid region dependent on agriculture. Their primary goal is to provide information needed by current and future decision-makers to develop water policies benefiting people, economies and ecosystems.

”Time and time again, society has adapted to less water in ways that can end up making us better off,” Biggs said.

Farmers adapt

San Diego State University geography professor, Trent Biggs/SDSU

Imperial Valley’s history as an agricultural center began in the early 20th century when ambitious irrigation projects first brought Colorado River water to the area. Eventually, the demands of growing populations along the river’s route from the Rocky Mountains to the Gulf of California forced a continuing series of cuts in water allocations for agriculture.

Farmers in the valley have so far adapted to reductions in imported water by implementing conservation and efficiency measures, even leaving some fields unplanted in exchange for payments from the Imperial Irrigation District, ultimately funded by the San Diego County Water Authority.

While Biggs stresses the researchers’ job in the Imperial and Mexicali Valleys is to document the issues, not suggest solutions, preliminary data point toward a few new ideas worth exploring. One possibility: Farmers may be able to continue improving water efficiencies by switching crops without sacrificing revenue or reducing the workforce.

Biggs said most of the water used by Imperial Valley agriculture now goes to alfalfa, grown as animal feed. But salad greens and other grocery produce could bring in more money for the same amount of water, he added. Switching crops also could contribute to the Imperial Valley’s growing importance as a driver of California’s aggressive emissions reduction plan. Already, the region is bustling with clean energy projects—wind, solar and geothermal.

However, even the most well intentioned water conservation methods can have unforeseen consequences. For example, new concrete liners have minimized leakage from old earthen irrigation canals in Imperial Valley. But Mexican farmers who depended on that seepage into underlying aquifers are seeing their land dry up.

“The whole idea of saving water often means taking supposedly “wasted” water from another user,” Biggs said. “So we’re not sure what the ultimate impact of conservation policies will be on the water balance of the region. One of the big questions we’re looking at is: What is the future of the Imperial and Mexicali valleys under reduced water supply?”

The first step in answering that question is documenting and quantifying the impacts of current water and land use policies. To gather this data, Biggs and his students combine high-tech and old-school research methods: satellite photos and in-person interviews.

“We’re interested in using satellite imagery to see where groundwater levels and water quality are changing and where we should talk to people to learn how those changes have affected them,” Biggs said. “Our goal is to understand the cause of shifting land use in their fields and how are they responding.”

Mixed methods

Kris Taniguchi using GoPro for 3D terrain mapping/Biggs Watershed Science Lab

Graduate student Joel Kramer used this approach in gathering data for his master’s thesis. He first mapped water scarcity effects by noting the appearance or disappearance of green crop areas in satellite images of Imperial and Mexicali valley farms. Then he and the undergrads he mentors drove out and asked some 25 farmers in Mexico how those visible changes had affected them.

Gabriela Morales, also an SDSU master’s student, was drawn to this mixed-methods research model after completing her bachelor’s degree at UCLA last year. She chose the study of geography over more heavily quantitative environmental sciences because of geography’s emphasis on human interactions with natural processes. Morales hopes her eventual findings will inform future water policy.

“I want to create a holistic view of what’s happening; I want to connect people to the environment,” Morales said.

Biggs considers the kind of fieldwork done by his students in Imperial Valley as an invaluable part of any educational experience in geography. To understand big problems, you need to see them firsthand.

“Meeting the people affected, hearing their stories, seeing it happen in front of your eyes—it’s hugely motivating and hugely educational,” Biggs said. “You get experience with how knowledge is created and discoveries are made. You see how stuff you learned in class came to be. You understand the problems and nuances that go into testing hypotheses and making statements about how the world works.”


Used by permission. This story is featured in the spring 2019 issue of 360: The Magazine of San Diego State University. 

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