Cows graze along the ribbon of the Rio Grande in Mineral County, Colorado, as it flows downstream from the San Juan Mountains. (Photo by Diana Cervantes for Source NM)
The Rio Grande existed long before humans. It may not outlive us.
Through millions of years, the river is mapped in strata, in oral traditions. More recently, in computer models.
All tell of rapidly receding waters. A shrunken Rio Grande remains for thirstier landscapes and wildlife drawn to its banks. For people, too.
The river is low because people take from it, and because we reshaped it — both exacerbated by climate change, said C. David Moeser. He built a model in 2021 mapping the impact humans have on the Rio Grande’s watershed for the U.S. Geological Survey.
The model depicts what the river looked like before people started diverting and storing the river’s water. At Fort Quitman, Texas, there was a 95% reduction in flow, he said. “And that’s not climate change,” he said. “That is strictly from anthropogenic change — how we have manufactured the system.”
There wasn’t much water to take from to begin with, he said, as climate change and human impacts stack on top of one another.
“The Rio Grande was never this mighty river,” he said. “But we are now losing the pulse of snow melt that we were using for irrigation.”
Humans straightened the river, cutting off the marshlands. We lined canals with concrete, built dams and reinforced banks. All in the name of efficiency — to create storage and reserves, or to move water from one place to another.
The loss of water translates to fewer wildspaces on the river. Since 1918, the entire stretch of the Rio Grande has seen a 90% reduction of wetland habitat, according to a 2020 restoration feasibility study from the U.S. Army Corps of Engineers.
Climate change is a huge deal, Moeser acknowledged, but it’s an even bigger deal because of what people have done to the river over time.
Even still, “anthropogenic change is by far the largest change that we have in the Rio Grande basin,” he said.
The Rio Grande’s injuries are more visible now than ever. In 2022, there were gaping wounds, stretches of cracked riverbed revealed, all the way into New Mexico’s largest city, Albuquerque, as days slipped into weeks without rain. Irrigation seasons are shortened statewide, fields fallowed. Some species take one step closer to the brink of extinction every year.
Glenn Patterson spent 30 years as a hydrologist in the National Forest Service and has taught introductory water law at Colorado State University for over a decade. Adapting to drought, he said, means reframing how we see the system in the long-term.
“With climate change, we’re seeing increased variability, so that when droughts come, they tend to be more intense, and perhaps longer duration,” he said. “They’re interspersed with periods where stream flows and rainfall are greater than normal for a while, and then the variability swings, and drought comes again.”
A monsoon can get the river moving again and soothe those cracked, visible beds for a bit, but it’s not enough to reverse desertification. Deluges from stronger storms can lead to a pattern of flooding, especially in recent burn scars, posing threats to crops, homes and water supplies.
This is the tale of one of the biggest rivers in the West, in crisis now after millions of years of existence, injured by people and human-caused climate change.
In the coming days, Source New Mexico will present a series of stories that span nearly 700 miles of the Upper Rio Grande, from the headwaters in Colorado to the Forgotten Reach about 100 miles inside Texas, along the U.S.-Mexico border. Loss and heartache flow through them as the river suffers. Eddies of denial surface, and some seedlings of restoration. But even those are under threat.
These are the narratives that shape people who live along the river, just as we shape its waters.
This project was funded by a grant from the Water Desk and by States Newsroom, a network of nonprofit news organizations and home to Source NM.
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