Annual precipitation has decreased in New Mexico since the 1990s, leading to more groundwater pumping amid a drought.
This article appears in the February 2024 issue of The American Prospect magazine. Subscribe here.
“They’re a really beautiful thing to look at. From a vantage point on a mountain looking down, it looks like a huge human circulatory system, the veins in a leaf or the lines on your hand,” says Paula Garcia.
The executive director of the New Mexico Acequia Association is describing over 800 acequias that run through the state. These ancient water systems could serve as a low-tech solution to one of the Western United States’ most intractable problems in the age of climate change: how to ensure water in an increasingly dry region is distributed equitably and efficiently.
The word acequia is Spanish, but comes from al-saqiyah in Arabic, which can refer to both a water-carrying device or someone who bears water. As they exist in New Mexico, acequias are irrigation systems that use gravity chutes to transport water. While some stretches of these networks use metal pipes, most are just open ditches. After diverting water from a river, the network “takes water into what is called an acequia madre, the mother ditch, that then separates into brazos, branches, that take water to the fields,” Garcia explains.
Acequias lack many of the hallmarks of modern water sourcing, such as man-made dams to control the flow of rivers or pumps to pull groundwater to the surface. That makes them feel like a relic of a pueblo past; and indeed, an acequia today looks very similar to what it would have looked like 100, 200, 300, or even 400 years ago.
In practice, shifting from large industrialized water systems to community-oriented ditches won’t be easy.
Unlike in past centuries, however, the Southwest today is experiencing an unprecedented dry period. The past two decades have seen some of the most severe water scarcity on record, according to the U.S. Geological Survey. Not only has there been less precipitation, but because of higher temperatures, evaporative demand has increased by 16 percent since 1980—meaning that what water does fall does not last long in the region’s streams and rivers. The current megadrought in the Southwest shows no signs of ending.
Acequia-inspired water partitioning practices may prove a better method to manage such conditions. “One of the main lessons from acequias is how to deal with a finite resource [especially] regarding climate change which just exacerbates the scarcity,” says Garcia. The question now is how to convince the people of the modern Southwest—from the farmers of California’s Central Valley to the growing retiree community to their representatives in state capitals and D.C.—that a centuries-old water management system is actually their best bet to survive the future.
Helping to Recharge
While acequias can help cope with water scarcity, their physical infrastructure might offer a future for recharging groundwater, which is increasingly being depleted.
Since 2004, three-fourths of the losses in the Colorado River Basin have been groundwater. Given that groundwater made up 26 percent of freshwater usage in the United States as of 2015, using it at the same rate could significantly worsen water scarcity. But reducing groundwater use, particularly in the Southwest, could prove to be difficult, as regions with less precipitation depend on it more for irrigation.
Acequias do not rely on groundwater for irrigation, which relieves pressure on the underground reservoirs known as aquifers. These aquifers recharge slowly, so if fewer farmers and residents are pumping from them, that can slow the rates at which groundwater dries up.
This independence from relying on groundwater also allows acequias to be adaptable to wet and dry periods.
“Annual precipitation in the ’70s, ’80s, and into the ’90s in New Mexico was higher than it’s been before and after. The agricultural systems that can pump groundwater are set up for that precipitation regime, and they’re pumping groundwater in excess of precipitation now that we are in a drought,” says Sam Fernald, director of the New Mexico Water Resources Research Institute and professor of watershed management at New Mexico State University.
Acequias have been adapting to wet and dry periods in this region for 400 years, making them more equipped to handle water scarcity. “If there’s less water available in a given year, the irrigation footprint goes down. If you get a lot of water in a wet year, the irrigated footprint expands and the irrigation covers more of the landscape,” explains Fernald.
Apart from being adaptable and not relying on groundwater, Fernald says acequias can even help to recharge groundwater and increase the amount of water in the watershed, because they “rely on gravity flow that’s based on surface water, and it’s in balance with that renewable supply.”
They might even be able to mitigate the effects of climate change that is disrupting the irrigation schedule. Increased temperatures have led snow to melt from the mountaintops earlier in the spring and flow downstream. When that happens, the water can be unusable, because ditches haven’t been opened to irrigate fields where no crops have yet been planted.
Traditional acequias, however, have unlined ditches, which allow runoff water to seep back into the ground and eventually back into rivers and streams, replenishing groundwater in aquifers. “This is a way to actually ameliorate the impacts of climate change [and] keep water higher in the watershed for longer,” says Fernald.
Modern water infrastructure practices, such as lining ditches with polymer or storing water in dams, actually decrease the replenishment rate, since unused water is unable to seep back into the ground and eventually back into rivers.
An acequia uses gravity chutes to transport water for irrigation.
No Juniors or Seniors
Right now, the laws that govern water usage throughout much of the Southwest—Arizona, Colorado, Nevada, New Mexico, Texas, and Utah—are based on a doctrine of priority, or “prior appropriation.” What this means, says Adrian Oglesby, an expert in water law and policy and professor at the University of New Mexico, is that whoever purchased water rights earlier—“senior” water users—will receive, in full, their contracted amount of water, even if doing so means there will be no water left to meet the contracted amount of water of “junior” users who purchased water rights later. Think of it as a “first come, first served” framework. When there is not enough water to go around, junior water users might have their water shut off to meet the contracted needs of the senior water users.
The acequia, on the other hand, employs what Garcia calls repartimiento, or shortage sharing, a system in which “a person’s water right is dependent on how much actual water there is.” There is no concept of a senior or junior water user, and as a result, water rights on an acequia are not quantified in acre-feet, gallons, or any other measurement of volume. Instead, a person’s water rights are defined in time. For example, as part of an acequia, I—along with every other member—would get “four” water rights. That means that when there is plenty of water, I get enough for four days of irrigation per week. But when there is a drought, that might mean just four hours.
This ensures that everyone still receives a percentage of their water rights, instead of some people being shut off to accommodate the contracted amount of water someone else might be owed. It prioritizes the greatest number of people receiving the water that is available, rather than the person with the oldest contract getting their full allotment before everyone else.
Figuring out who wins and who loses has been one of the key issues at hand when it comes to one of the biggest water crises in the U.S. over the past two years: divvying up the Colorado River, which provides water to parts of California, Nevada, Arizona, Colorado, New Mexico, Utah, and Wyoming, and the country of Mexico. In 2021, the federal government declared a shortage in the Colorado River, due to the ongoing regional drought and the fact that the “paper water” (the volume of water each party ostensibly owns) established in the 1922 Colorado River Compact no longer remotely reflects the true amount of “wet water” (the amount of water the river actually has).
The Biden administration warned the states that if they didn’t come up with a plan to cut water use by two to four million acre-feet per year, the federal government would have to step in. It took nearly a year, but in May 2023, the states finally reached a consensus, proposing that California, Arizona, and Nevada cut water use by three million acre-feet by 2026, among other fiscal details.
Oglesby draws parallels between the Colorado River pact and the acequia ideology: “The two primary practices of maintaining high levels of water user engagement and cooperation and the avoidance of priority enforcement through negotiated shortage sharing are already being adopted and practiced across the increasingly arid Southwest,” he said. “The recently negotiated settlement between California, Arizona, and Nevada is a high-level example of that.” But rather than a high-stakes negotiation, acequias build that cooperation into their very process of distributing water.
A Cultural Shift
Despite the wet winter of 2023 in California, and an El Niño forecast that should keep the state drought-free in 2024, nobody expects the Southwest’s water problems to be over. And despite the Colorado River agreement, nobody expects that the fights over water in the region have been permanently resolved.
Acequias sound like a great option to distribute available water equitably, at least in theory. But in practice, shifting from large industrialized water systems to community-oriented ditches won’t be easy. First, acequias are not a protected practice federally or in all Southwestern states, and there would be legal barriers to challenging corporate water companies with any changes. But perhaps more important, there’s a cultural shift that comes with putting the community over the individual, a rare concept in our profit-driven economy.
Individuals who use these systems acknowledge this reality. “It is a cultural practice, grounded in the cultural values of sharing … It’s not something that you can force people to do. It really has to happen from a place of understanding and empathy,” says Garcia. She added, “It gets lost in the technical issues of infrastructure and water rights, but [the acequia’s] essence is sharing water and sharing labor, and that magical combination makes the water flow.”
Jock Jacober, president of the Sangre de Cristo Acequia Association based in San Luis, Colorado, told me, “I happen to philosophically believe that it is the proper way to manage natural resources on Earth … The acequia is the kind of method that would be useful to human beings if they could cooperate and learn how to use their resources … In the face of climate change, these kinds of practices are going to become more important.”
As far as expanding acequias on the political side, researchers like Oglesby believe that there is more to be done to “increase education among our decision-makers about creative alternatives to priority enforcement.” While it can’t be predicted how acequias might grow throughout the Southwest in the future, their communal legacy of acequias will undoubtedly live on.
