Climate model projections indicate that New Mexico's future will be warmer and drier, with diminished water supply from the Rio Grande, presenting extreme challenges for policy makers and agricultural stakeholders. A new study titled, “Adapting irrigated agriculture in the Middle Rio Grande to a warm-dry future" analyzed the long-term tradeoffs of land and water management interventions that could help irrigated agriculture adapt to growing water scarcity in a desert environment.
David Gutzler, a professor in the Department of Earth & Planetary Sciences at The University of New Mexico (UNM), along with UNM students and collaborators at other regional universities led by the University of Texas-El Paso, delved into the potential impacts of various intervention scenarios on agricultural water supplies in the Rio Grande Valley downstream of Elephant Butte Reservoir.
This research has a big impact on New Mexico because while this study focused on hydrology and climate change, there is also a big component of water management associated with interstate and international agreements to share water. The research was carried out with the engagement of communities that share river water and groundwater in southern New Mexico, western Texas, and across the border in the Mexican state of Chihuahua.
Climate model projections indicate that New Mexico's future will be warmer and drier, with diminished water supply from the Rio Grande, presenting extreme challenges for policy makers and agricultural stakeholders
The research analyzed 19 different intervention scenarios, including the implementation of deficit irrigation, changes in cropping patterns using existing crops, and the introduction of new drought- and salt-tolerant crop alternatives. Hydrological simulations were conducted using the soil and water assessment tool (SWAT) model, considering the limitations of the model in performing scenario simulations.
“We carried out a six-year effort with a big interdisciplinary team, including hydrologists, economists, and agriculture experts, to explore the water future of the transboundary region along the Rio Grande, and to think about potential ways that the community could adapt to projected diminished water supplies,” said Gutzler. “The principal UNM-based component of the research was to make projections of future river flows into Elephant Butte reservoir. We started with US Bureau of Reclamation model projections of natural river flows in a future climate warmed by increasing greenhouse gases. But we couldn't use the natural flow projections directly. The actual Rio Grande flow that reaches Elephant Butte is nowhere near natural because we're withdrawing lots of the water upriver, putting it to beneficial use in Colorado and northern New Mexico. So, our research came up with a way to turn the simulated natural flows reaching the reservoir into something more realistic, accounting for upstream water withdrawals.”