Gwynne Ann Unruh is an award-winning reporter formerly of the Alamosa Valley Courier, an independent paper in southern Colorado. She covers the environment for The Paper.

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So what is a “zombie idea”? According to a paper written by an international research team examining water conservation, “A zombie idea is one that has been repeatedly refuted by analysis and evidence, and should have died, but clings to life for reasons that are difficult to understand without further investigation.”

The belief that modern irrigation technologies can save significant amounts of water drives billions of dollars of investments into modern irrigation technologies every year. To find out why the perception that investment in complex modern irrigation systems saves water continues to resurrect itself zombie style, the international research team reviewed more than 200 supporting research articles on drip, sprinkler and traditional water systems. Their research paper “Agricultural water saving through technologies: a zombie idea” was published in the peer-reviewed journal Environmental Research Letters in November 2021.

The team looked at how this zombie idea forms; why it persists, even when proven wrong by scientific evidence; and how to overcome it. The international team included: Frank Ward, Department of Agricultural Economics, New Mexico State University; C Dionisio Pérez-Blanco, Department of Economics, Universidad de Salamanca, Spain; Adam Loch and David Adamson, School of Economics and Public Policy, Centre for Global Food and Resources, The University of Adelaide, Australia; and Chris Perry, Consultant, London, UK.

Flood Irrigation Has History Here

Agriculture in the Rio Grande floodplain has been significant since prehistoric times. Water is a very scarce resource in the high mountain deserts of New Mexico and farming techniques have not changed much in thousands of years. Traditional irrigated farming remains the most important form of agriculture across the state.

Native Americans were the first inhabitants in the Land of Enchantment and various Tribes and Pueblos farmed and hunted on the land the Rio Grande flowed through for at least 10,000 years before Europeans came.  The river supported more than 100 Pueblos with well-developed and sophisticated water harvesting and irrigation techniques in place centuries before the Spanish and the Mexican settlers arrived. The new settlers brought with them the communal irrigation and management structure associated with the current acequias irrigation systems.

The King of Spain, and later the Governor of New Mexico, bestowed land grants to individuals based on prior service or loyalty from the 1600s through the 1800s. These grants usually contained sufficient land and water resources to facilitate settlement and the establishment of communities. Many of New Mexico’s acequia systems are legally defined within those land grants. There are a total of 295 land grants recognized in New Mexico and at least 700 acequia irrigation systems.

Each influx of settlers into New Mexico expanded or constructed the acequia systems until they stretched into the San Juan Basin, the San Luis Valley of southern Colorado and the tributaries of the Canadian water river in the east. The communal approach to water distribution, shared equally, evolved further in response to drought.

Modernizing New Mexico’s Irrigation Systems

The concept of modernizing New Mexico’s nearly 700 acequia irrigation systems to save water is an intriguing one. According to the latest available state engineer report, irrigation accounted for 76% of water withdrawals in New Mexico in 2015. With climate change, population growth and drought increasing daily, upgrading the acequia system to a drip irrigation or sprinkler system is an idea that many might think makes a lot of sense. The research team found out it does not.

The team found “the assumption that modern irrigation technologies save water, has been refuted by analysis and evidence, should be dead – yet it lives on.” They said the impacts of complex modern irrigation systems usually have the opposite effect to what was intended. Any water ‘saved’ is likely to be at the expense of return flows to aquifers or drains. If these are a source of water to other users, any local benefits are largely offset by negative impacts elsewhere.

NMSU Research Team Member Weighs in on Research

The Paper spoke with research team member Frank Ward, distinguished achievement professor at New Mexico State University’s College of Agricultural, Consumer and Environmental Sciences.

“Water conservation is very hard to measure as everyone has their own view on what water conservation is. Drip irrigation is very attractive to some because it applies much, much less water than surface or flood irrigation. It also costs a lot. The drippers need cleaning, the animals get in. It’s a mess,” Ward said.

He said people typically do drip irrigation on a very small scale, or for very high value crops, as it can be quite profitable. “The only problem with drip is, when you grow your crops with drip irrigation, your yields and production per acre go up. In a dry place like New Mexico the problem with higher crop yields is they very often give rise to higher water consumption.”

Ward explained that though you apply less water under drip than you do in traditional irrigation, you actually consume more water as the yields and production go up. And, there is reduced recharge into the aquifer basin around Albuquerque.

“Historically there is an assumption that shifting into drip irrigation will conserve water, but very, very few studies have been done that have measured that, and those that have measured it have found that in a lot of cases it can increase water consumption.”

“It can increase income and increase yield. It’s good for food security, you get more calories into people’s bellies. But it doesn’t necessarily conserve water.  The water that would have gone down into the land to recharge the aquifer basin under flooding irrigation, disappears or nearly disappears,” he said.

The Rio Puerco watershed, located beneath the The Navajo Chapter community of To’Hajiilee, 30 miles from Albuquerque and completely within the Middle Rio Grande Underground Water Basin, ran out of water twelve years ago, What water remains is filled with corrosive dissolved solids, looks like orange juice, resembles coffee grounds and smells like rotten eggs.

Ward said people are looking at legislative enactments and proposals on subsidizing drip irrigation to combat water shortages. The researchers concluded “abandoning the zombie idea that conversions to modern irrigation technologies will save water is a prerequisite to achieving sustainable water and economic security.”

The research team’s paper states: If the objective is saving water, resources are better employed in researching and testing the feasibility and performance of transition pathways towards transformational institutions and policies that are effective in saving water (such as quotas or charges), rather than in subsidizing modern irrigation technologies that increase consumption and aggravate scarcity.

South Valley Farmer Weighs in on Water Use

I spoke with Marcia Fernandez who has a small farm in the South Valley that is both irrigated from the Rio Grande and also has drip irrigation from their well. Fernandez said there is a misconception that farmers are wasting all the water.

“A county commissioner said we need to go to drip irrigation. To which I say, you can’t drip irrigate all crops. You might be able to drip irrigate a cornfield or potato field or a chili field with a lot of money, but you can’t irrigate pasture or alfalfa or crops that you feed to animals,” Fernandez said.

Fernandez uses drip irrigated groundwater that comes out of a well for their garden. “Your yields are very good with drip irrigation. You have good control of how much water you’re bringing from underground, however the water you are bringing up is highly mineralized water that includes a huge number of salts. Most of them are calcium salts, but there are others and your ground eventually becomes unusable and unreliable.”

Fernandez said once you’ve added the salts as a foreign element to the dirt your crops yields will ultimately go down. “The dirt becomes literally white from the calcium build up and it looks like you have thrown flour on your dirt and that’s a big problem. We drip irrigate what we can and we flood irrigate the rest when there’s water,” she said. “The water from flood irrigating is returned through groundwater absorption into the shallow aquifer, which eventually makes its way to the deep aquifer.”

When the Rio Grande went dry in July, it was a big moment for the Middle Rio Grande acequias. “We asked the Water Utility Authority to declare a stage three water emergency which would mean no outdoor watering, but they just looked at us and said: ‘You guys are crazy. We have enough water for 100 years.’

“That’s literally how they are viewing this,” Fernandez said. “The utility authority doesn’t ascribe to the Native wisdom that you need to consider the results of your actions for seven generations after you. Why are they not panicking about it? Their hair should be on fire about this, but it’s not.”

Fernandez has had the hills and slopes of their land scanned with a laser and leveled for more efficient irrigating. There’s a lot of work and money involved in maintaining drip irrigation as the salt accumulates inside of the drippers and other equipment, and they have to be replaced frequently. Fernandez said the city of Albuquerque and Rio Rancho and others who have their straws in the deep aquifer are beholden to the people who are helping recharge the aquifer as the figures of recharge to the river now are pretty low. She said the farmers that flood irrigate are contributing huge amounts of water to the deep aquifer and she advocates paying the farmers of cultural lands and the Pueblo of Sandia for recharging the aquifer.

“We are helping to keep the aquifer of Albuquerque afloat. People’s lands are laser leveled. We are required to finish irrigating one acre in one hour. The farmers don’t waste water, we’re not running water out into wastelands, we’re not running water over roads or have sprinklers watering the sidewalk,” she said. “Farmers have done a good job of using just what they need and no more.”