Declining flows that have left the Rio Grande a tenuous brown ribbon through Albuquerque this summer are a reminder both of the impact of climate change, but also of our reliance on increasingly fragile water management infrastructure, according to a University of New Mexico writer and researcher studying the history and future of the state's water management.
While climate change is driving the Rio Grande's overall flow down, the failure of El Vado Dam on the Rio Chama has taken away one of central New Mexico's most important tools for managing the resulting risk, explained John Fleck.
Built in the 1930s on the Rio Chama in northern New Mexico, El Vado Dam changed the flow of the Rio Grande, storing water during high spring runoff to allow irrigation – and river flows – in late summer when the river would otherwise nearly dry up, explained Fleck, who is Writer in Residence at the Utton Transboundary Resources Center at the UNM School of Law, Professor of Practice in the Department of Economics, and former director of UNM's Water Resources Program.
El Vado has been out of commission since 2022 because of leaks, and the U.S. Bureau of Reclamation has said it will be years – it is unclear how many – before it can be fixed.
Prior to El Vado's failure, water stored behind the dam would be slowly released over the summer months to support Middle Rio Grande Valley irrigation, and also the river's environmental needs, explained Fleck, who with UNM Regents Prof. Robert P. Berrens is writing a book about the history of Albuquerque's relationship with the Rio Grande.
"The way it changed the flow of the river is central to what our modern Rio Grande is – a river that had more reliably continuous flows in late summer when El Vado was in use," Fleck explained.
El Vado was built in the 1930s by the Middle Rio Grande Conservancy District, a local government agency formed to bring flood control, and drainage of swampy lands, to New Mexico's Middle Rio Grande Valley. The primary goal of the project was city-building, enabling the modern city of Albuquerque to grow up on the valley floor, Fleck and Berrens argue in their forthcoming book.
As part of the project, the Conservancy District consolidated irrigation systems in the valley, and built El Vado to support efforts to develop commercial agriculture in the valley. The design for El Vado was unusual – an earthen dam with a steel face plate. It is that steel plate – an unusual design – that poses the current problem, leaking in ways that the U.S. Bureau of Reclamation decided posed serious danger.
Efforts to fix the dam have faltered, and the Bureau of Reclamation is now searching for a new approach.
In the meantime, Albuquerque is adjusting to a fundamentally changed river. Reduced flows in late summer the last few years have increased risk to the Rio Grande silvery minnow, an endangered fish that has dominated river management in recent years.
The Albuquerque Bernalillo County Water Utility Authority has been forced to shut down summer diversions to meet Albuquerque's drinking water supplies, shifting to groundwater pumping, which places further stress on Albuquerque's heavily taxed aquifer.
And irrigators throughout the valley have seen reduced water supplies, making farming in the valley harder.
It's an example of what Fleck called a "coupled human and natural system", with problems caused by failing infrastructure piled on top of the already hard problems posed by declining river flows as a result of climate change. "We have a change in the climate," Fleck said, "which means the amount of water and the time of the water changes. But also all this infrastructure is, like, 100 years old."
