In early May of the year 1519, an opulent procession of Aztec nobles and priests disembarked from the Aztec capital of Tenochititlan by canoe en route to the Temple of Tlaloc, built on the summit of Mount Tlaloc, at “the meeting ground of Earth and sky.” This procession was undertaken after the long, dry winter in the expectation that the appeasement of Tlaloc, the Aztec god of rain, would bring back the all-important summer rains, and with it, nature’s abundance.

This procession brought with it offerings of food, jewelry and, most importantly, an innocent young child. Dressed in their finest costumes, the nobility performed elaborate prayers and rituals in the temple space. Finally, after assembling the offerings upon an alter at the foot of Tlaloc’s idol, Tlaloc’s priest slaughtered the child, and bathed the offerings in the child’s sacred, innocent blood.

This ritual would have been repeated year after year into the future, but if a Spanish conquistador named Hernán Cortés had not arrived in Central Mexico that November on a plunderous expedition for gold and silver. The demise of the Aztec Empire is well documented and will not be rehashed here, but suffice to say, Cortés, his men, and rival indigenous groups finally dispatched with the mighty Aztec Empire in 1521, after a bloody conflict that destroyed the great Aztec capital of Tenochititlan. In the years that followed, the Spanish Empire built Mexico City directly atop the ruins of Tenochititlan as an act of symbolic dominance.

The Spanish not only sought control of the people of the Aztec Empire, but also the fertile valley that had sustained and enriched them. While Tenochititlan had existed in a close partnership with Lake Texcoco, the shallow lake which surrounded the city, the Spanish soon set about a campaign to drain the lake and channel away the rains in order to achieve a new urban typology that fit their colonial ambitions. Their unbalanced approach to water management, which can be simplified as “exploit and drain,” has accelerated in modern times, with consequences that have increasingly dire implications for the future of Mexico City.

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Museum depiction of Temple Mayor facade. Photo by Daniel Alvarado.

Today, Mexico City faces one of the worst water crises in the world, due to rapid population growth, poor resource stewardship, and the compounding effects of climate change. Flooding, ground subsidence, water contamination, and shortage-induced social unrest are just a few of the city’s daily problems. In addition, the constant threat of a major earthquake looms heavily, as a rupture of the fragile water distribution and sewage systems could threaten the Federal Government’s stability and the city’s very existence.

The Federal District and the surrounding states have begun to tackle these issues with various initiatives aimed at improving conservation and efficiency in the water infrastructure in the Greater Mexico City region. However, as we will posit in this article, it has become clear that piecemeal conservation solutions will not be enough to support Mexico City in the long term. Large scale, regenerative approaches are being sought out that leverage the natural features of the region, while historical methods of water management and irrigation, and contemporary ecological design solutions are being explored to stabilize the city’s water metabolism and restore the region’s natural systems.

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Xochimilco Park, last remnants of Aztec Chinamapa and canal system, UNESCO World Heritage site. Photo by Daniel Alvarado.

But in order to fully contextualize the current conditions of Mexico City, we must first understand the unique spiritual connection between the Aztecs, the Valley of Mexico, and Lake Texcoco. In this first piece of a two-part article, we will outline the water management approach of historic Tenochtitlan. In the second piece, we will look in detail at what challenges Mexico City faces – and what regenerative design solutions are being posited to solve them.

Tenochititlan was an improbable city built in the middle of Lake Texcoco, at the lowest point of the Valley of Mexico. With canals for roads, a lake for a moat, and the innovated Chinampa agriculture system, the Aztec Empire’s population exploded from a small wandering tribe in the late 1300’s to an immense empire by the sixteenth century – the size and complexity of which rivaled Rome. They achieved this wealth in large part due to their deeply imbedded spiritual relationship with the Valley of Mexico.

The sacrifice of a young child at the Temple of Tlaloc, for instance, was in the Aztecs’ view not an act of cruelty but one of utmost importance spiritual importance. The cycles of nature, which are explained by the Mesoamerican “Cosmovision,” were perpetuated by a strict regimen of ceremony, war, and blood sacrifice. The rising sun, changing of the seasons, and passage of time itself all depended on adherence to this religious regimen, or punishment would be dealt in the form of drought, famine or worse.

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Temple Mayor ruins today. Photo by Daniel Alvarado.

Considering the existential importance of the Cosmovision to the Mesoamerican people, it is no surprise that their cities were built in as close harmony with their environment as possible. In Nahuatl, the Aztec language, the word for city is Altepetl, or “mountain filled with water.” As thus, their cities, and in particular their pyramids, were built to symbolize the many mountains in the Valley of Mexico that were thought of as hollow vessels filled with water. This water was drawn up from Tlalocan, the watery underworld realm of Tlaloc, to provide for the people of the earth. Meanwhile, the summits of the mountains connected to the celestial realm, where other important deities such as Quetzalcoatl resided.

This sacred and ecologically integrated city design manifested in spectacular displays of coexistence with nature – the evidence of which can be read in the famous firsthand account by the Spanish solider Bernal Diaz del Castillo, in which he describes Tenochititlan as thus:

“…When we saw all those cities and villages built in the water, and other great towns on dry land, and that straight and level causeway leading to Mexico [i.e. Tenochtitlán], we were astounded. These great towns and cues [i.e., temples] and buildings rising from the water, all made of stone, seemed like an enchanted vision from the tale of Amadis. Indeed, some of our soldiers asked whether it was not all a dream…”

He goes on:

“… I was never tired of noticing the diversity of trees and the various scents given off by each, and the paths choked with roses and other flowers, and the many local fruit-trees and rose-bushes, and the pond of fresh water. Then there were birds of many breeds and varieties which came to the pond. I say again that I stood looking at it, and thought that no land like it would ever be discovered in the whole world… But today all that I then saw is overthrown and destroyed; nothing is left standing.”

Through Bernal Diaz’ description, we can catch a glimmer of the immense beauty of the Aztec capital. This beauty was also functional, as we know that integration with nature was inherent to the city’s design. For instance, the long causeways not only provided transportation, but in some cases brought fresh water from mainland springs and rivers via aqueducts. The main aqueduct, drawing water from Chapultepec Springs, brought water over three miles in a dual pipe system into the city center, likely filling the fresh water ponds that Bernal Diaz describes. The biodiversity that he describes also demonstrates the Aztecs’ integration with nature, who understood on both a spiritual and biological level the importance of a diverse food source. In fact, there was a specialized class of horticulturalists who were responsible for the planting of trees and crops, all according to the Tonalamatl, or Book of Days.

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Diego Rivera Mural depicting Tenochtitlan and the fresh water canal. CC by Ckn8u.

The Aztecs were ambitious engineers of their environment, as is demonstrated by their vast use of dikes, canals, and artificial islands. However, these engineering projects generally worked with natural systems, rather than against them. For instance, a system of dams and levees allowed for control of flooding in the rainy summer, and water retention in the dry winter. The Dike of Nezahaulcoyotl spanned the entire eastern expanse of the main lake, helping to separate brackish water from the fresher water near the agricultural zones. This enabled large scale cultivation of reed plants, an important resource for the production of their ubiquitous woven goods. In the southern lake of Xochimilco they constructed vast artificial island gardens – Chinampas – that fed nearly half of the city’s population of at least 200,000. The Aztecs cleverly dealt with sanitation and fertilization with a single system – human waste was captured and transported by canoe to the Chinampas to replenish the agricultural soils A small portion of the historic Xochimilco Chinampa system has been preserved as a World Heritage Site in southern Mexico City, and will be described in detail in the second part of this article.

It is important to note that while the Aztecs lifestyle in the Valley of Mexico was extremely well adapted, its long term sustainability was questionable. At the time of the Spanish conquest, deforestation, overexploitation of water and soil resources, and rapid population growth were straining the region. Whether or not the Aztecs were headed for a Mayan style implosion is a question that can never be answered, as the Spanish colonizers took a completely different approach to water management in the colonial era. The Spaniards saw the Valley of Mexico as an environment to be dominated, rather than integrated – a strategy that has been continued to the extreme through contemporary times.

In the second article in this two-piece series, we look at how Mexico City has dealt with its recent water crisis.