Category: Americas

Source: The Conversation – USA – By Ari Caramanica, Assistant Professor of Archaeology, Vanderbilt University

Seeing the north coast of Peru for the first time, you would be hard-pressed to believe it’s one of the driest deserts in the world.

Parts of the region receive less than an inch of rain in an entire year. Yet, water and greenery are everywhere. This is the nation’s agro-industrial heartland, and, thanks to irrigation canals, almost every inch of the floodplain is blanketed in lucrative export crops, such as sugarcane, asparagus and blueberries.

However, the apparent success of this system masks an underlying fragility.

Water shortages have plagued the region for centuries, and now modern climate change combined with agro-industrial practices have further intensified droughts. In response, the Peruvian government has invested billions of dollars in irrigation infrastructure in recent years designed to deliver more water from a resource more than 100 miles away: glaciers in the Andes.

But the Andean glaciers are disappearing as global temperatures rise. Peru has lost over half its glacier surface area since 1962. At the same time, floods often connected to wet El Niño years are increasing in both frequency and intensity. These floods often destroy or obstruct critical irrigation infrastructure.

As an archaeologist investigating societal responses to environmental and climate disaster in Peru, I’m interested in unraveling the histories of complex systems to understand how to improve similar systems today. To understand the Peruvian heartland’s vulnerabilities, it helps to look to the deep past.

Most of the modern canal network originally dates to pre-Hispanic times, more than 1400 years ago. However, evidence suggests that while the canal systems of the past may have looked similar to those of the present, they functioned in more efficient, flexible ways. The key to adapting to our present and future climate may lie in comprehending the knowledge systems of the past – not just the equipment, technology or infrastructure, but how people used it.

An environment of extremes

The north coast of Peru is an environment of extremes.

In this desert, thousands of years ago, societies encountered many of the same challenges posed by the modern climate crisis: expanding drylands, water scarcity, vulnerable food production systems, and frequent, intense natural disasters.

Yet, people not only occupied this area for millennia, they thrived in it. Moche and Chimu societies created sophisticated, complex political and religious institutions, art and technology, and one of the largest pyramidal structures in the Americas.

When the Spanish arrived on the desert north coast of Peru shortly after 1532 C.E., early chroniclers remarked on the verdant, green valleys across the region.

The Spanish immediately recognized the importance of the canal network. They had used similar canal technology in Spain for centuries. So, they set about conscripting Indigenous labor and adapting the irrigation system to their goals.

Just a few decades later, however, historic records describe sand dunes and scrublands invading the green valleys, water shortages, and in 1578 a massive El Niño flood that nearly ended the young colony.

So how did the Indigenous operation of this landscape succeed, where the Spanish and the modern-day agro-industrial complex have repeatedly failed?

Culture was crucial for ancient canal systems

Ancient beliefs, behaviors and norms – what archaeologists call culture – were fundamentally integrated into technological solutions in this part of Peru in ancient times. Isolating and removing the tools from that knowledge made them less effective.

Scientists, policymakers and stakeholders searching for models of sustainable agriculture and climate adaptations can look to the archaeological record. Successfully applying past practices to today’s challenges requires learning about the cultures that put those tools to work effectively for so long, so long ago.

The pre-Hispanic societies of Peru developed agricultural principles around the realities of the desert, which included both dry seasons and flash floods.

Large-scale irrigation infrastructure was combined with low-cost, easily modified canals. Aqueducts doubled as sediment traps to capture nutrients. Canal branches channeled both river water and floodwater. Even check-dams – small dams used to control high-energy floods – worked in multiple ways. Usually made of mounded cobble and gravel, they reduced the energy of flash floods, captured rich sediments and recharged the water table.

The initial failures of the Spanish on the north coast exemplify the problem of trying to adopt technology without understanding the cultural insights behind it: While they may be identical in form, a Spanish canal isn’t a Moche canal.

Spanish canals operated in a temperate climate and were managed by individual farmers who could maintain or increase their water flow. The Moche and Chimu canal was tied to a complex labor system that synchronized cleaning and maintenance and prioritized the efficient use of water. What’s more, Moche canals functioned in tandem with floodwater diversion canals, which activated during El Niño events to create niches of agricultural productivity amid disasters.

Desert farming required flexibility and multifunctionality from its infrastructure. Achieving that often meant forgoing impermeable materials and permanent designs, which stands in stark contrast to the way modern-day water management works are constructed.

Copying ancient practices without the culture

Today, the Peruvian government is pushing forward with a decades-old, multibillion-dollar project to deliver water to the north coast from a glacier-fed river.

The Chavimochic project promises a grand transformation, turning desert into productive farmland. But it may be sacrificing long-term resilience for short-term prosperity.

The project feeds on the temporary abundance of glacial meltwater. This is creating a water boom as the ice melts, but it will inevitably be followed by a devastating water bust as the glaciers all but disappear, which scientists estimate could happen by the end of the 21st century.

Meanwhile, sustainable land management practices of past Indigenous inhabitants continue to support ecosystems hundreds and even thousands of years later. Studies show higher levels of biodiversity, crucial to ecosystem health, near archaeological sites.

On the Peruvian north coast, pre-Hispanic infrastructure continues to capture floodwater during El Niño events. When their modern-day fields are flooded or destroyed by these events, farmers will sometimes move their crops to areas surrounding archaeological remains where their corn, squash and bean plants can tap into the trapped water and sediments and safely grow without the need for further irrigation.

Critics might point out the difficulty of scaling up ancient technologies for global applications, find them rudimentary, or would prefer to appropriate the design without bothering with understanding “the cultural stuff.”

But this framing misses the bigger point: What made these technologies effective was the cultural stuff. Not just the tools but how they were used by the societies operating them. As long as modern engineering solutions try to update ancient technologies without considering the cultures that made them function, these projects will struggle.

Understanding the past matters

Archaeologists have an important role to play in building a climate-resilient future, but any meaningful progress would benefit from a historical approach that considers multiple ways of understanding the environment, of operating an irrigation canal and of organizing an agriculture-based economy.

That approach, in my view, begins with saving indigenous languages, where cultural logic is deeply embedded, as well as preserving archaeological and sacred sites, and creating partnerships built on trust with the people who have worked with the land and whose cultures have adapted their practices to the changing climate for thousands of years.

Ari Caramanica receives funding from The National Endowment for the Humanities.

– ref. Peru’s ancient irrigation systems succeeded in turning deserts into farms because of the culture − without it, the systems failed – https://theconversation.com/perus-ancient-irrigation-systems-succeeded-in-turning-deserts-into-farms-because-of-the-culture-without-it-the-systems-failed-251199