Nov 02, 2017
The subsoil of the capital of Mexico has suffered since the Conquista
The largest city in the world, Mexico City, is supplied by millions of liters of water for various “basins”, a basin are the spaces where the rains fall to accumulate and integrate into rivers, lakes or the sea. Mexico City is surrounded by mountains and was built on top of a large lake, the lake of Texcoco. From the Spanish invasion, achieved by Hernán Cortés in the name of King Charles I of Spain and in the name of the Spanish Empire between 1519 and 1521, the advanced engineering that the ancient mexicans had built was demolished. They decided to cover the beauty of their lakes, without living in harmony and bending the legendary spaces of the city. Today, this location is covered by a large urban spot that developed over the years a series of disasters and floods that also make up the history of the city.
The aquifers that sustain it descend radically 13 cm each month, about 3 million cubic meters of water annually, they come to extract unimaginable and unbalanced figures of water from the subsoil of the city. These channels are currently contaminated with various toxic wastes such as sewage, industrial waste and different types of bacteria making these rivers useless within the ecosystem.
This harmful abuse to the subsoil causes in some areas of the city to sink to 2.5 cm per month (satellite Sentinel ESA, European Space Agency), causing a sinking of 15 cm to 30 cm per year. This revealed for example in the Zocalo of the capital, new archaeological vestiges just below the cathedral. It should be mentioned that to recover a balance in the groundwater flow we would have to stop pumping and wait 32 years.
In 1910 they created a drainage system that worked with the pressure generated by the own angulation and gravity of the valley, but in 2002 already there was a sinking of approximately 9 meters. Therefore it had to be replaced by parts and an expensive system of bombs was integrated to extract what before it climbed on its own account.
The city’s own growth is mostly by “chic apartments, office building and family flats” authorized in risk areas, with low cost materials to save on expenses. Many of these projects get authorization through bureaucratic processes thanks to corrupt or “under water” payments public officials accept of the different municipalities. These buildings claim more water than the underground aquifer can tolerate and eventually they will have to look for water more deeply, thus, inevitably creating a huge instability through the Earth’s hollows creating “authorized” landslides in earthquake zones. In turn, the displacement of the subsoil and the transit of heavy transport break pipes, which causes leaks, leaving no water to 40 percent of the neighboring communities to these areas and forcing them to wait the mainly centrals to activate the pumps under pressure, or the arriving of a pipe to supply the water they need.
After the 2017 earthquake, several engineers and architects are looking for environmental solutions for the recovery of these natural channels and basins, uncovering them instead of extracting water from neighboring cities and building living wetlands with biological filters, like plants or gravel.
The area that occupies the Mexican capital is within a basin with 7 lakes and 45 rivers, thousands of hectares that need live rivers, to have ecosystems with less pollution, which causes more than 10 thousand deaths a year and there will be less risk of landslides before the possible earthquakes that will continue to occur in the future.
Reviving the rivers for an apparent utopian CDMX of the future would cost an estimated 863 million dollars, a little less than the budget that ends in the construction of roads and highways for automobile use. This investment would bring social and environmental benefits to Mexico City and these rivers would not end up in drains and there would be more environmental awareness among its inhabitants.
Latin American Post | Aldo Leal Larroa
Copy edited by Laura Rocha Rueda