Researchers at the University of Arizona are working on groundwater and agricultural research to help guide sustainable farming practices in central Arizona.
This project $10 million grant It integrates more than 20 experts from institutions in Arizona, California, and New Mexico, led by the University of California, Davis, from the U.S. Department of Agriculture’s National Institute of Food and Agriculture.
“We need research. We need to know what’s going on in this area. I can do it.” look Ron Rayner, a longtime farmer with large-scale operations in Arizona and California and a member of the project’s advisory board, said:
As a major drought dries up the Colorado River’s reservoirs and imposes water cuts, farmers in the Southwest are turning to groundwater to sustain operations. According to project leaders, this is causing unprecedented overdrafts in aquifers in California’s Central Valley, Central Arizona, and New Mexico’s Lower Rio Grande Basin.
A multi-state groundwater research project aims to reduce impacts on aquifers while helping farmers and irrigation districts adapt to new realities.
In Pinal County, where deforestation on the Colorado River was most severe, growers saw an 87% reduction in surface water allocations from one year to the next. This year we will receive 5% of the 2021 allotment due to an external agreement.
“Basically,[the Central Arizona project]is going back to the days before surface water existed,” said Maricopastanfield Irrigation and Drainage District farmer and board member, who also sits on the university project’s advisory board. Association member Brian Hartman said.
The district first received water from the Colorado River through the CAP Canal in 1987 and was expected to maintain it through at least 2030. The district is currently running about 99% on groundwater.
Farmers used CAP water all the time, so the aquifer experienced significant recharge. Irrigation districts and other bodies have long earned “credits” for leaving water underground. They can now use those credits to pump water.
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“[They]haven’t lost their groundwater extraction rights, so some people are entitled to reclaim those credits, but farmers still have full extraction rights,” says the UA Water Resources Research. Director of the Center and Projects in Arizona.
Many water users are now competing for the same resource. According to Megdal, it’s like having two straws running underground: a credit straw and an agricultural straw, both drawn from the same aquifer.
Hydrologists, engineers, plant and soil scientists, economists, agricultural extension experts, and educators in USDA-funded projects develop management strategies and use data for better decision-making. We are working together to integrate. The project will end in his August 2026.
Water quality and availability
The Arizona team, including Megdal, soil health expert Debankur Sanyal, and graduate researcher Simone Williams, focused primarily on building water quality models, assessing soil health, and developing water availability scenarios. I’m here.
On Tuesday, the team met at the Maricopa Agricultural Center to share project progress and hear input from project advisory board members.
Williams uses a hydrological model called the Soil and Water Assessment Tool (SWAT) to measure and predict the impact of irrigated agriculture within the Pinal Active Management Area on groundwater availability and quality. Created to enforce groundwater abstraction regulations, the AMA covers most of the county’s agricultural land. While quantity is clearly a widespread concern, Williams suggests quality isn’t getting enough attention.
As water resources become more limited, salinity, nitrates and other contaminants in nearby wells will become a more pressing problem.
opinion:How to make the Colorado River sustainable in the long term
“We are in a semi-arid region, so most people focus on the amount of water. I have added the results. It may help raise awareness about this issue.
Water quality is already a litigious issue in Pinal County. In 2020, the Ak-Chin Indian community, located in the northwestern part of the county, filed a lawsuit against two irrigation districts that the tribe said were mixing poor-quality groundwater with surface water from a central Arizona project. rice field. receive.
High levels of salt can affect the growth and health of many crops. Potatoes grown on Ak-Chin farms are particularly susceptible. The tribe has seen yield declines. Most of the farmers in Pinal District have grown salt tolerant forage crops.
Fertilizers can also leach high levels of nitrates into aquifers, making the water unsafe to drink. The model can inform farmers and irrigated districts about the quality and nutrient content of the groundwater they are using, indicating treatment needs and reducing fertilizer inputs and costs.
Once the project is complete, the public will be able to access the model via an interactive online tool. Because the model works at the sub-basin scale (there are 33 in Pinal AMA), the user can see which section of the aquifer is pumping water.
Cover crops for soil health, irrigation techniques
Debankur Sanyal believes that improving soil health could provide a return on investment even in limited water scenarios, such as those faced by Pinal upazila farmers.
The obvious challenge of not having enough water for additional crops can have positive benefits for the farmer and the land. It can be efficient, Sanyal said. Working with farmer partners, he is testing several summer cover crops at eight field sites and monitoring their impact on the soil.
The project also aims to define soil health indicators specific to the Central Arizona region, enabling farmers to make better decisions to improve soil health and productivity. The research project also takes into account the investment and returns from planting these crops.
The water outage from the CAP has already forced many Pinal County farmers to leave half of their land unplanted.
Unfortunately, dramatic water disruptions create opportunities to scale up irrigation technology and better practices, said Isaya Kiseka, an associate professor of agricultural hydrology and irrigation at the University of California, Davis, and the project’s principal investigator. rice field.
In California, farmers’ interest in irrigation monitoring and technology, as well as technical consulting, has increased with the implementation of water restrictions through policies such as the state’s Sustainable Groundwater Management Act. A similar thing could happen in Arizona, he said.
“This policy has created an environment conducive to these technologies, many of which are not new,” Kisekka said. Many farmers opted out because they didn’t see a significant return on investment, but that decision could change in the current scenario. ”
Clara Migoya is responsible for environmental affairs for the Republic of Arizona and azcentral.Submit a tip or question clara.migoya@arizonarepublic.com.
Environmental coverage at azcentral.com and in the Republic of Arizona was supported by a grant from the Nina Mason Pulliam Charitable Trust. For the Republic’s Environmental Reporting Team, follow @azcenvironment on Facebook, Twitter, and Instagram at environment.azcentral.com.
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