Tenochtitlan and Floating Gardens

Tenochtitlan, the seat of the Aztec empire, was founded in 1325 and was situated on an islet in the middle of Lake Texcoco in the Valley of Mexico. When the Spanish conquered the city in August of 1521 after an eight month siege, the city was destroyed. In its place, Mexico City was established. At the time, Tenochtitlan was one of the largest cities in the world. Population estimates range from 100,000 to 300,000.

The links above are from Wikipedia. There are so many history resources available that recount those events and detail the culture of that time. It was hard to pick one aspect to share with you. When I was reacquainted with Tenochtitlan during a research tangent, the small pox outbreak brought by the Europeans that killed a third of the inhabitants of the valley was what kept me reading on. What has stayed with me though and kept my creative mind ticking away is the feat of civil engineering that was Tenochtitlan.

The Aztec city-states in the valley were hydraulic societies. They used bridges, causeways, dikes, sluices, canals, aqueducts, terrace farming, and chinampas (artificial, floating gardens) to sustain the population and allow for navigation about the city. The city was quartered into campans or zones with twenty calpullis or districts in each. There were main roads and canals crossing the calpullis. Bridges were made to be removed at night in defense of the city. While the idea of symmetry excites me, it is the amount of planning in advance for growth that I find jaw dropping. Each calpullis had a market. Public buildings that served spiritual and educational functions were in the center of the city. All new development had to be approved by the city planner, the calmimilocatl.

The Tenochtitlans used the aqueduct water from Chapultepec for bathing and cleaning. They used mountain spring water for drinking and cooking. Residences had private bathrooms and public ones were made available. What I found fascinating is that roughly one thousand men would float through the city collecting garbage and human waste. That waste was used along with lake bottom sediment to fertilize the crops grown on the chinampas.

The chinampas answered my biggest questions. How did Tenochtitlan manage to feed its population? How did the city expand in the middle of a lake? It turns out that the lake was not deep. Each of these gardens was built in a very shallow location. It was staked and then fenced in with waddle. The lake bed was dredged for its rich sediment, and the beds were built up with this material along with decaying vegetation. Trees were sometimes planted as anchors. Canals separated the chinampas.  These raised beds were above lake level. As the beds dried and expanded, the city’s land surface did as well. The lake on the other hand shrunk. The growing system was so efficient that the chinampas could turn three crops a year.

I searched floating gardens on the net to see what I might come up with. Several articles can be found discussing the Aztec chinampas. Believe it or not, the Hanging Gardens come up as well. I also found a cool instructional article, “Floating Gardens in Bangladesh.” The floating garden is suggested as a sustainable way to overcome land scarcity and flooding in Bangladesh.

Vincent Callebaut is an architect with an eye on the future. He has designed a whale- shaped floating garden. Its primary purpose is to filter out pollutants from the world’s rivers. He has another biomimicry design meant to imitate lily pads.  These are intended to serve as sustainable floating cities whose residents are climate change refugees that lost their homes to rising ocean levels. He has also proposed a floating vertical garden tower the looks like a pair of dragonfly wings for New York City’s Roosevelt Island. This is another example of urban farming and would also augment an island as the chinampas once did. While this urban farming skyscraper by Romses Architects does not float, it does take into account the reuse cycle apparent with the chinampas.

The how-to article and the project examples offer food for thought and possible plot bunnies. In the articles pertaining to the buildings, utopian and dystopian come up. It isn’t only about the future though. It’s terrific is that these new concepts draw from such an old technology. The answers to current problems might be arrived at after an exploration of the past. I’d love to hear your thoughts on the matter. Where would chinampas fit in your story? If you have any fictional examples to recommend, please include links or at least the title and author in comments.

When Mexico City was built on top of what was Tenochtitlan, the dams were destroyed and never reconstructed. The city dealt with constant flooding. The conquistadors began draining the lake as they settled into the city. The five lakes that were situated in the valley are now considered extinct even though a small portion of Lake Texcoco still exists in Mexico City. When I return later this month, it will be to discuss the long term effects of this development and how the concepts might be useful in fiction.

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