Tosin Olofinsao was looking for water in the wrong place. As a researcher at the University of New Mexico, he expected to find that a handful of massive agricultural operations drove water consumption across the drought-stressed Middle Rio Grande Basin. What he discovered instead would reshape how policymakers think about conservation in one of the Southwest's most critical river systems.
The Middle Rio Grande Basin, a dryland region in central New Mexico, is already under significant strain from climate change, shrinking water supplies, and competing demands from agriculture, cities, and ecosystems. Against this backdrop of water scarcity, Olofinsao and his mentors—Associate Professor Jingjing Wang and Regents Professor Robert Berrens—set out to understand who was actually using the water and how. Their work, published in the journal Sustainability, combined satellite data, crop maps, groundwater records, agricultural census records, and GIS analysis to create a detailed map of irrigated agriculture during the severe 2021 drought year.
The study's most striking finding: thousands of small farms collectively use more agricultural water than large commercial operations. While individual large farms consume more water per operation, the sheer number of micro-scale and small irrigators in the basin means their combined water use represents the majority of agricultural consumption. Specifically, small irrigators account for 55.9% of evapotranspiration—the water that evaporates from soil and plants—across the entire basin. This matters enormously for water management, because it means conservation strategies that focus only on the largest operators miss more than half the problem.
The researchers also uncovered a sharp disparity in how farms access water during droughts. Large commercial operations were far more likely to have access to irrigation wells, giving them flexibility to pump groundwater when surface water runs low. Many smaller farms, by contrast, rely primarily on surface water deliveries from the Rio Grande system, leaving them vulnerable when drought tightens the supply. This inequality shapes what gets planted and how much water gets used. Alfalfa and hay crops account for nearly three-quarters of total crop water use in the basin—crops that, while relatively tolerant of deficit irrigation, still demand substantial water.
Beyond the numbers lies a deeper truth that Olofinsao emphasized in his research: agriculture in the Middle Rio Grande Basin is not merely an economic enterprise. Many small farms are woven into family traditions, cultural heritage, open space preservation, and local identity. They benefit from tax exemptions for greenspace and provide non-market values that pure water accounting cannot capture. This reality complicates the work of designing conservation policies, because efficient water management cannot simply be imposed from above.
The findings point toward a new approach to water governance in the region. Rather than focusing on large farms alone, policymakers and water managers will need to work directly with thousands of small irrigators. The researchers suggest voluntary fallowing programs, seasonal deficit irrigation, and water leasing strategies as possible tools—approaches designed to reduce water demand while supporting farming communities. In a region where climate stress is only expected to intensify, understanding where water actually goes is the first step toward making sure it reaches those who need it most.