The Green Revolution is ancient

New Mexico, the second driest state in the USA, has never been ‘naturally green’. But it has been ‘culturally green’ for centuries, thanks to an ancient communally-managed water infrastructure known as acequias that sees water as a shared natural good, not a commodity. 

Renewed attention to such ancient systems is part of a worldwide rediscovery of “green infrastructure” vs ‘grey infrastructure”, with cities accommodating and working in harmony with water rather than trying to control it by concreting canals and building dams.

While used for irrigation in Spain, the Andes, northern Mexico, and today’s American Southwest for at least 400 years, the system dates back at least to the eighth century, when Arabs and Berbers colonized Spain using water conservation techniques developed in the desert. In South America, it may be even older.

“The Islamic agricultural revolution was the first green revolution,” says University of Granada archaeology professor José María Martín Civantos, who is leading the MemoLab project, which aims to restore the region’s hydrological network during prolonged drought. The Arabs and Berbers “transformed the way water is used in the Mediterranean.”

The MemoLab project restored ancient canals in Granada, Spain.

By controlling the flow of rain or snowmelt, the acequia system absorbs water into the land to replenish the aquifers. Civantos calls it “sowing water”, a term that also can be heard in Peru. “When I was a boy, I heard my parents say that we had to ‘sow’ the water at the top,” said Calistro Lopez, who is working on restoring the amunas. “Now I understand it.” 

It reminded me of how Zimbabwe’s legendary ‘water man’, the late Zephaniah Phiri Maseko, talked about ‘planting water’.  He turned a barren plot into an oasis by capturing rainfall with basins, swales and stone dams. The concept actually reflects a sophisticated understanding of the ‘full water cycle’.

“The basic requirement for the system to work is that the channel isn’t too permeable and has a gradient that maintains the correct flow of water. Then you need a community of people to maintain it,” says Sergio Martos-Rosillo, a geologist involved in the MemoLab project. 

“The system is efficient, the aquifers get replenished and no technology is required,” he says. “It’s much more manageable and adaptable than building a dam and much more resistant to climate change.”

Just as people in New Mexico manage the acequias cooperatively, restoring the Aynadamar ditch in Spain’s Granada region was done by community volunteers. It began in October 2022 and was inaugurated on April 15, 2023.

In Spain, Civantos says one of the challenges for MemoLab was trying to recover the collective knowledge of ordinary people that was lost during the Catholic reconquest of Islamic Spain and expulsion of the Muslim population in the 17th century. “People don’t think peasant farmers could devise anything this complex,” he says. “You can’t understand the glory of Córdoba or Granada without understanding that what lay behind it was the wealth created by a form of agriculture that was much more advanced and productive than elsewhere in Europe.”

In Peru, scientists are also working with farmers to restore a system of ancient canals known as mamanteo to address Lima’s increasing water shortage, reflecting a state commitment to supporting green infrastructure. The system, which may be at least 1,400 years old, funnels water from highland streams into the mountain itself, where it percolates through cracks and natural aquifers over months to emerge in springs and natural reservoirs.

Various projects to restore amunas have taken place or are underway.  In Huarochiri, Aquafondo began restoring the amunas with local participation in 2017 and has identified 67 kilometers to be reclaimed by 2025, said Aquafondo director Mariella Sanchez Guerra. As well as serving Huarochiri, the amunas feed the Santa Eulalia river, a tributary of the Rimac river that provides some 80% of water consumed in Lima.

The investment in green infrastructure makes it “very affordable” in contrast to building a canal, said Fernando Momiy, the president of Sunass, Peru’s national water regulator. “Lima is a desert city which keeps growing and in five years there will be another 700,000 inhabitants who will need water,” he said in 2015 when the state funding began. “That’s why we need to look at combining grey infrastructure with green infrastructure.”

“It’s the first time that a regulatory body has promoted this kind of infrastructure in Lima. We see that there’s a lot of focus on grey infrastructure when we should be looking at green infrastructure, so as not to have to invest so much in expensive grey infrastructure.”

In drought-stricken New Mexico, there has been much interest in  Aracely “Arcie” Chapa’s documentary, Acequias: The Legacy Lives On.

PBS offers the full documentary to watch.

Through the eyes of farmers, advocates, scholars, practitioners, lawmakers, journalists and community members,  it tells the story of New Mexico’s acequias, which it calls water democracies.”The subject matter is important,” he says. “People are really wanting to see a film about acequias and treat it with historical context. That’s a real interest to people. Especially here in New Mexico, acequias are a lifeline for many people.” 

These ‘ancient’ technologies reflect a deep awareness of the importance of the full water cycle, so often disrupted by modern developments which mean the land can’t absorb rainfall. So repairing water systems means recognizing the need for integrated management of land and water – a point made in a documentary film funded by the Center for Regional Studies at the University of New Mexico.


Peru harnesses ancient canal system to tackle Lima water shortage. Guardian, Jun. 22, 2015

Spring time: why an ancient water system is being brought back to life in Spain. Guardian, Apr. 11, 2022

Facing a Future of Drought, Spain Turns to Medieval Solutions and ‘Ancient Wisdom’. New York Times, Jul. 19, 2023

In Peru, pre-Columbian canals offer hope against drought., Apr. 22, 2021

Documentary looks at the history and impact of acequias on New Mexico and its people. Albuquerque Journal, Jun. 8, 2023

Cover image: This image of the amunas in the mountains above Lima appeared in’s article.