Xochimilco . . . floating gardens that fed an Indigenous megalopolis

by Richard L. Thornton, Architect & City Planner

One Summer In Mexico – Part Eight – July 12, 1970

Alcaldía de Tlalpan – Ciudad de México

During the Twentieth Century, the universal marketing symbols of Mexico in the United States were the Pyramid of the Sun at Chichen Itza and Xochimilco Gardens. On this day, 50 years ago, I finally got to see Xochimilco. Also, Professor Soto persuaded Mexican soldiers to let us visit a place where agronomists and civil engineers were recreating the agricultural landscape of Anahuac, 500 years ago.

Today, Sr. Soto invited the whole family and me to join him on a tour of the campus of the Universidad Nacional Autónoma de México (UNAM) and Xochimilco Gardens. I have finally figured out that he is using me as an excuse to bring the family together. Jose’, Lupe, Gionela and Ruth had not been on family outings together, since the girls became teenagers.

The main library at UNAM is world-famous architecture.

I was totally overwhelmed by the scale of the national university. UNAM is the oldest university in the Americas and is the number one ranked academic institution in the Spanish-speaking world. In 1970, it had 107,000 students, of whom over 24,000 were females. At the time, Georgia Tech had only a little over 11,000 students. UNAM now has about 362,000 students, while Georgia Tech has about 32,000 students.

The sudden appearance of over 24,000 single, career-oriented females, who were for the first time since the Spanish conquered Mexico not under the direct control of males 24/7, was spear-heading the rapid social and political changes in Mexico. The gals at UNAM were demanding a true democracy, the placement of females in administrative positions, legal equality, political equality and the legalization of birth control pills. Today, the Mexican Congress has about the same percentage of women (38%) as legislative bodies in the Nordic countries. Currently, only 18% of the members of the US Congress are female.

This is one minute section of the UNAM dorm complex, which was the 1968 Olympic Village.

The reader will recall from Part Seven that Alicia at age 20 had virtually no legal rights, while Mexican men were assumed to be full adults at age 18. Mexico was then burdened with the old Spanish legal system, which viewed females as the chattel of either their father, male guardian or husband. It was impossible to enforce these old laws at the UNAM dorms or at the conventional apartments, where many of the coeds lived.

The boat dock at Xochimilco Gardens in the summer of 1970. Note the slimy green algae growing on the surface of the polluted water!


In contrast, I was totally underwhelmed by Xochimilco Gardens. If the Okefenokee Swamp is a “10,” the Xochimilco Gardens is a “1” at best! The photos that you see in the media, which are used to promote tourism, completely misrepresent the place. The “gardens” are nothing, but an old drainage canal along which somebody planted Lombardy Poplars in the early 1950s. Most of these trees were dead in 1970 due to the extreme level of pollution in the water.

The water smelled like a sewage treatment plant and the short bayou was crowded with boats. I asked the Soto’s, if they really wanted to ride in one of the boats, because I didn’t. They nodded their head in agreement, We got back into the car, after I took a few photos.

All that is left of a once large Lake Xochimilco is a swampy area of Mexico City with many drainage canals. The green reservoir is for water control.
Xochimilco Gardens is now called the Xochimilco Ecological Park. The boats only travel on the relatively short, ink-colored canal.

While driving into the “gardens” I noticed a sign that denoted a joint project of INAH and UNAM. There was a narrow sandy road leading off through a forested area. My INAH ID Card gave me the right to visit any archaeological site in the republic and even interview personnel (as I did at Tenayuca) if they were not too busy. Sr. Soto was game for an adventure. The women were indifferent.

The ladies elected to wait under the trees, next to a pond.

We drove to the edge of the trees and then a squad of soldiers surrounded the car. They were pointing M-16 assault rifles and sub-machine guns. The lieutenant ordered Sr. Soto and I to get out of the car. He glanced into the car and saw upper middle class women, who didn’t look at all like terrorists, so waved the other soldiers to lower their weapons. He asked Sr. Soto to step away from the car to have a chat with him.

Sr. Soto soon showed him his ID card as a professor of biology at the Politecnico. Sr. Soto then waved his hand for me to join them. The lieutenant asked for my INAH ID. When he saw my home address, his eyes lit up, he smiled then spoke in perfect English, “I know Georgia! It is a beautiful state. I have attended several classes at Fort Benning. Do you know Lake Lanier? It is the cleanest lake water that I have ever seen.” The lieutenant waved the other soldiers to go back into the woods then we had a little chat with him.

Well, we had stumbled upon a fascinating project, which is now well known, but then was a secret. The Mexican army officer didn’t see any problem with us seeing it, since Sr. Soto was a university biology professor and I was a guest of Relaciones Culturales . . . destined 15 years later to be named Soil Conservation Service Farmer of the Year! Alicia would be proud of me!

Healthy grass near irrigation ditches indicates low levels of pollutants. As you will see in the video below, the dead Lombardy poplars in this photo have been replaced by new, thriving trees . . . now that the water in the ground is no longer poisonous.

Civil Engineers and anthropologists from UNAM were constructing new chinampas or floating man-made islands then experimenting with aquatic agriculture or aquiculture. They first wanted to better understand how the Mexica (Aztecs) were able to feed the hundreds of thousands of people in Anahuac with these floating islands. The next phase was to develop standard engineering plans for building modern floating islands in the freshwater wetlands in southern Mexico so the nation would be better able to feed its exploding population.

The lieutenant apologized for carrying the submachine gun then walked over to one of his men and asked him to hold it for awhile. He then offered to lead us on a tour of the new chinampas. Sr. Soto and I were delighted. The ladies elected to go wait under the shade of a tree.

This lieutenant was quite knowledgeable about the scientific principles involved. The scientists had discovered that several types of chinampas were needed. Maize (Indian corn), leafy vegetables, beans and strawberries each had their own soil and moisture requirements.

The biggest problem that they were having was storm water . . . polluted storm water to be specific. Xochimilco was one of the lowest sections of the metropolitan Mexico City area. Much of the region’s highly polluted storm water flowed into Zochimilco and nearby Chalco. Petroleum-based chemicals “killed” the soil. That is why the trees were dead and most of the ancient chinampas had been abandoned. Very little would grow in the soils containing high levels of petroleum-based products. The UNAM scientists had to truck in “clean” soil from Chalco to build their new chinampas.

There was another problem . . . biological pollution. The waters flowing out of the slums of Mexico City could have been used for biological warfare. They were chock full of parasites and pathogenic microbes, including killers such as salmonella, typhoid and cholera. The chinampas had a reputation for killing their farmers and the people, who ate the farmer’s produce.

One can see today on the satellite imagery that the Mexican scientists solved the water pollution problem by getting their civil engineering partners to design a super-sized water treatment reservoir, plus dykes to separate toxic water from cleaner water. The pioneering research by teams of professors and students at the Universidad Nacional Autónoma de México has been applied to farms throughout the world, even the United States. This is the Mexico that North Americans rarely, if ever, learn about in our highly ethnocentric news media.

Today, clean water is stored in a separate lake, which is the location of most artsy photos in Xochimilco.
The construction of greenhouses (upper right) have made possible the year-round production of food, strawberries and flowers in Xochimilco.

Fifty years later . . . a big success story

You probably noticed in the news this spring, a story that first aired on CNN. The Covid19 pandemic was royally screwing up the food delivery network for metropolitan Mexico City, which now has 24 million people, rather than the 8 million that kept me disoriented. Local government officials offered all of the unused chinampas in Xolchimilco and Chalco to local farmers. The program was an immediate success and will continue after the Pandemic subsides. Below is a recent documentary that describes the current status of the 50 year long Xochimilco Agricultural Development Project.


  1. Howdy, This is the first I had heard of different soil/moisture levels. How large was the Army project?

    On Tue, Jul 14, 2020 at 11:10 AM The Americas Revealed wrote:

    > alekmountain posted: ” by Richard L. Thornton, Architect & City Planner > One Summer In Mexico – Part Eight – July 12, 1970 Alcaldía de Tlalpan – > Ciudad de México During the Twentieth Century, the universal marketing > symbols of Mexico in the United States were the ” >

    Liked by 1 person

    1. It was not an army project. They were just guarding the site. Without guards, people came in and stole the vegetables and farming equipment. I didn’t put anything in my notes about the size, but I guess it was about 10 acres, where they had the test plots.


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