Mexico: A City on a Lake

Mexico City’s history traces to the 14th century, when Tenochtitlán became the island capital of the Aztec Empire. It was situated on Lake Texcoco in the upland Valley of Mexico.

The city’s troubled relationship with water also dates to the time of the Aztecs. Heavy seasonal rainfall and flash flooding were common and could prove devastating to agriculture when Texcoco’s salty waters mixed with the fresh water of interconnected lakes. The Aztecs offered human sacrifices to Tlaloc, the god of rain, in hopes of protection and abundance. On a more practical level, they also became adroit water-management engineers.

Their hydraulic infrastructure included dams and aqueducts that provided fresh water for drinking; irrigation ditches for agriculture; and canals, causeways and bridges for transportation. In a kind of Venice-of-Mesoamerica, canals flowed through the city and between the chinampas (raised crop beds, or “floating gardens”), which provided much of the population’s food.

The Aztecs learned to control the water level by rerouting rivers and springs, and cleared forests and drained the lakes to strategically gain land, but in doing so they inadvertently altered the water cycle. The result was that both erosion and the impact of flooding began to increase.

Even more far-reaching changes to the valley commenced with the arrival in 1519 of Hernán Cortés and the conquistadors. The Spanish were in awe of the city’s size and magnificence, comparing it favorably to cities in Europe. One of the invaders noted, “These great towns and cues [temple-pyramids] 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.” Cortés was eager to exploit the land’s wealth and within two years had overthrown the city.

But the Spanish, being used to arid climates, didn’t appreciate the dynamics of the natural setting. They could have capitalized on all that water, but they opted instead to conquer it too.

After 1521, the newcomers razed Tenochtitlán and built Mexico City, the capital of New Spain, on the ruins. While the Aztecs had skillfully managed the water that surrounded and sustained them, the Spanish settlers “paid little attention to the careful co-existence with water that peoples of the Valley had cultivated for generations,” writes Barbara Mundy, associate professor of art history at Fordham University and a specialist in 16th-century Mexico. “Instead,” she continues, “they started a new war against the water in the Valley. This war lasted over 400 years, as Spaniards and their Creole descendants tried to get rid of all of the water by draining the lakes. They searched fruitlessly for drains (thinking the lakes were like bathtubs with a plug), built tunnels through the mountains that caved in, changed the courses of rivers, all in an attempt to dry up the Valley, perhaps to turn it into bone-dry Extremadura [a region in Spain] of their ancestors.”

They cleared land to enlarge the city with ranches, orchards and homes for an ever-growing population. The colonists introduced their own flood-reducing schemes, which included new dams and canals to divert water from nearby lakes and rivers. With natural surface water sources having been systematically drained, most of what remained of the valley’s lakes dried up in the 20th century.

And so, where forests once existed, today we find farmlands and grasslands for grazing. Where lakes existed, we find human settlements built on dry lakebeds, with Greater Mexico City covering much of the valley.