As the forecasts for climate change become more and more evident, it is clear that Mexico City’s current water challenges are to become its most threatening. Drought alongside heavier but shorter rainfalls are creating extenuating economic and social demands for a population over 20 million. The political spectrum in the upcoming presidential and local elections this year, seems a latent problem to a still centralized society. The arrogance of man throughout the ages has turned what was once a splendid water prone area into a sprawling concrete parched megacity.
View during a rain storm of the main square of the Mexican capital, Mexico City, The once former Aztec capital Tenochtitlan once stood on this same square, surrounded by water and floating gardens before the Spanish colonization period decided to turn the area into squares and roads be draining the surrounding waters.
Hernan Cortes discovered Tenochtitlan, the Aztec capital as an environmental splendor, surrounded by water and floating gardens. The conquest of the new world, the creation of Mexico City along with the ignorance of the Spanish in understanding the highly complex and balanced water system successively led to more and more problems as they tried to create an urban landscape similar to Spain with squares and roads. The Mexican capital today is not only sinking, it’s parched and highly polluted by sewage floods.
Wokers along Mexico City's deep water drainage system, also known as the Emisor Central conducting repairs. Designed for a flow of 170 m3/s, the Emisor Central had zero gravity flow by 1990 and negative by 2000 due to further land settlement and the inclination of the original Grand Canal which until 1910 functioned on gravity alone.
Mexico City lies on a basin, one so large it was five lakes in the dry season and one large lake in the rain season providing plenty of fresh water. Today, the megalopolis has to dig deeper and deeper into the aquifers, often reaching fossilized water. Getting water to the city is as insane as it is modern. It’s a great engineering feat as well as an economic one, as it must bring as much as 40 percent of its water from remote sources but at the same time loses some 40 percent of its water in leaks. Over 750 billion liters of water must be expelled through a crumbling infrastructure that has yet to establish a rainwater collection or recycling wastewater system.
The completion of the Grand Canal in the late 1800’s was an attempt to control and drain northwards the rainfalls and the valley’s running river waters. The poor drainage, the overcrowding, the lack of knowledge on the clay ground floor has year after year continuously sunk the city, rendering the canal’s natural gravity flow practically useless. The sewage waters today have to be pumped out at a cost equivalent to the energy demands of the nearby city of Puebla with 4 million people.
A resident in the south of Mexico City walks through the entrance to her home after heavy rainfalls produced a flash flood that has overspilled the city's sewage systen The city of Mexico produces an average of 40,000 liters (10,570 U.S. gallons) of sewage every second.
Father and child walk along the open sewage Canal de la Compañia in the municipality of Valle de Chalco on the periphery border of Mexico City and the state of Mexico. The Canal de la Compañia drains the Mexican capital of its waste. The canal lies several feet above thousands of homes and is a major source o pollution and fears of flooding which have occured in the past, destroying hundreds of homes.
The southeast of the city is perhaps the most blatantly affected, the district of Iztapalapa with over 2 million people, many of which are accustomed to not having water from their taps, is covered with kilometer long cracks, crumbling sidewalks and crumbled buildings. Water for many residents only comes once a week, or through water trucks, known as “pipas”, every once every several weeks, depending on how large their home built cisterns are. The “pipas” are often government controlled by the political party in charge of the district, so adherence to the party often determines not only its arrival but its price.
In the district of Xochimilco, once the center of the Aztec’s floating gardens, known as “chinampas”, a dual phenomenon occurs. On the one hand, the communities in the hills have to pay for their water to be brought up with donkeys that either come from a well or a “pipa” delivery spot. Many families spend up to 10 percent of their income for water. On the other hand, the agricultural communities have had their water reservoirs drained while the city floods the canals with treated water. Many residents recall being able to step out of their homes and swim in clean waters when they were children. These lands were once lake beds and now drought and overexploitation rolls enormous dust storms through them.
Residents of Mexico City, in an effort to mitigate heat waves. swim in a pool that was formerly fed by a natural spring source, It was converted into a public pool and filled with treated waters and made available throughout the summer, Las Termans in the district of Iztacalco, Mexico City no longer functions as such in order to save water in the capital.
The situation does not only affect the lower classes. It is starting to become more and more common to see, gated communities in both the south and north of the city, ordering “pipas”. This is a large strain to the infrastructure because the wealthy are far more accustomed to using far more water and they can afford it.
Climate change in Mexico City is exposing its vulnerabilities but the consequences of the current situation date back to term after term of poor government management and overpopulation. Water, health, air pollution, flooding and landslides are all current and future challenges due to these water effects.
The crisis is extenuated further by uncontrolled urban growth, that has permeated large areas of land that were set aside for agriculture or preservation. The land in many of these areas is porous, lying on volcanic rock, rather than clay like most of the city’s central area. The clay areas are the most vulnerable to sinking as evidenced in the many lopsided buildings downtown.
The illegal and controlled urbanization of the chinampas (floating gardends) of the district of Xochimilco located in the south of Mexico CIty have severely deteriorated the water quality of its canals. The environmental area considered part of UNESCO's world heritage program has been neglected by city authorities allowing the urbanization of it to continue. The waters in the canal once fresh water are now refilled continuously by the city's water commission from treated or recyled sewage waters.
The city has expanded from being a mere 30 square miles in 1950 to 3,000 square miles by 2010. Development has surely kept the city vibrant and attractive, but the increase of roads has not diminished traffic which continues to fill the atmosphere with carbon dioxide. The concrete and asphalt covering the city, in the overcrowded hills for example, forces the rainwaters to take the natural course of the rivers that once existed but now, since it can no longer seep into the ground, the waters cause landslides and flooding as they drag with them enormous amounts of garbage clogging the sewage system. Add to this the deforestation of the hills surrounding the valley and it’s impossible to admit that man has created a new environment.
Residents of the southern district of Xochimilco in Mexico City line up to fenced well to collect drinking water. In theory only residents of the area are permitted to do so and in regulated hours. The residents once used to simply take water from the canals or from the springs but they have now been tapped and must feed the entire water system for the Mexican capital which suffers from water shortages.
In order to keep the Mexican capital from flooding, the city and the federal government began in 2007 the construction of the TEO (Easter Emitting Tunnel) and the Atotonilco residual water plant (fourth largest in the world), both still not completed. The TEO, which connects to the Grand Canal, is twenty meters in diameter and extends 60 kilometers from the north of the city to the Atotonilco plant. It has been highly contested as still being insufficient.
The consensus amongst the political class working with engineers, environmentalists, scientists and the society at large is that the problems are evident and the resources exist but corruption, electoral preferences and the lack of political will hinder the entire situation.
Mexico City today is no longer able to grow horizontally, there is simply no more space. The city now has a vertical building boom of malls, offices and apartments that is unprecedented. These ventures will only stress the water system further. The city parliament once had a proposal that all new buildings had to collect their own rainwater, unfortunately it has never been implemented and would have considerably changed the protocol for the city. In the meantime, a new airport is being built, with green intentions so far in words alone, but again, it’s being done precisely on a dried bed lake.
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Workers operating and building walls with a boring machine inside what has been billed as the world's largest drainage tunnel, TEO (Tunel Emisor Oriente) will serve as an alternative to Mexico City's Emisor Central drainage tunnel, and will double the city's discharge capacity to 150m3/s to cope with heavy precipitation during the rainy season.
Mexicans enjoy a sunday night around a sewage suction pit with a water fountain at it's surface in downtown Mexico City.