When Hernán Cortés arrived in the great Tenochtitlán in 1519, he was surely surprised to see a city built on an islet in the middle of the immensity of a lake that in reality was not just one, but the union of five water bodies; Texcoco lake in the center is surrounded by the lakes of Zumpango, Xaltocan, Xochimilco and Chalco. Billions of cubic meters of water made it seem like this natural resource could never run out, especially in a city like that. Today, 500 years later, we can safely say that Mexico City's drinking water has its days numbered.
Since colonial times, the Spanish decided to drain the lakes and build Mexico City on dry land. As the years passed, the rivers that remained in the city were piped to build large avenues on them. Thus, CDMX, being the most important business, political and cultural center in the country, began to grow its population significantly year after year, reaching 20 million inhabitants (CDMX and metropolitan area). For hundreds of years, the drinking water that supplied the population of CDMX was extracted from the rivers surrounding the city and, importantly, from the subsoil through wells.
As the economic activity and population of the Valley of Mexico increased, the demand for drinking water increased exponentially and in response to this growing demand, the Cutzamala System was inaugurated in 1982 with the purpose of offering an alternative supply to the City of Mexico. Mexico through a system of dams located in the State of Mexico made up of Valle de Bravo, Villa Victoria and El Bosque. The water extracted from the dams travels to CDMX through a pumping system that currently represents 30% of the water that supplies the Mexican capital. The rest corresponds to the extraction made from the aquifers.
The Cutzamala System has a capacity of 782.5 million cubic meters. Due to the overexploitation of dams combined with the droughts generated by climate change, the Cutzamala System is today on the verge of collapse. As of March 2024, the dams have a storage of 27% (207.4 million cubic meters), which represents the lowest value on record. The minimum operating level represents a storage of 17%. That is, if the Cutzamala System loses 10% of its current storage, it would no longer be useful to supply CDMX, so it would have to depend exclusively on water extracted from the subsoil.
As an example, the Cutzamala System has a capacity equivalent to 430 Azteca Stadiums. Since 2016, an average of 36 stadiums have been lost annually. Currently, storage equivalent to 114 Azteca Stadiums is available. When the Cutzamala System has 77 stadiums left, it will not be able to be used again to send water to Mexico City.
It would seem that there is still enough water, however, as can be seen in the graph, between 2022 and 2023 storage equal to 101 Azteca Stadiums was lost. If the trend continues, by this year (2024) the Cutzamala System will permanently stop working.
Historical extraction of water from the CDMX aquifer is not very different. For many years, exorbitant quantities of the vital liquid have been extracted that exceed the natural recharge that the subsoil captures through rainwater. In 1990, 507 million m3 were extracted and 279 million m3 were recharged, resulting in an annual deficit of 228 million m3. To date, 1,000 million m3 are extracted and 513 million are recharged for an annual overexploitation of 507 million cubic meters per year. The subsoil of CDMX annually loses the equivalent of 1.28 times the capacity of Lake Valle de Bravo.
This overexploitation has caused pronounced subsidence in some parts of the city ranging from 10 to 40 centimeters per year. It is enough to visit the Metropolitan Cathedral or the Mexico City International Airport to notice the arrangements that have had to be made to level the floors and stairs. But these sinkholes do not only affect buildings at ground level, they also have a very strong impact on the CDMX pipe system that distributes water to all municipalities. Because the sinking of CDMX is differential (it is not even across the entire surface, there are places that sink more than others), the pipes break and this causes 40% of the water that is distributed to be lost due to leaks in the hydraulic network. It is urgent to repair the pipe system (which, above all, has been installed for more than 60 years) to be able to take advantage of the water that is lost in leaks and stop the sinking of the city. For this to happen, the CDMX wells must stop being exploited and water must be injected into the aquifers to avoid future subsidence and the consequences that these generate on the integrity of the hydraulic network.
In the vicinity of CDMX there are water bodies and other wells that could be used to lower the extraction levels of both the aquifers and the Cutzamala System. In the municipality of Naucalpan is the Madín Dam and further north in Cuautitlán Izcalli is Lake Guadalupe, both of which could be connected to the supply system. Likewise, those located in Zumpango and Xico could be added to these water bodies, where the latter would significantly help bring water to municipalities that suffer from severe shortages such as Iztapalapa. The investment to carry out the works that allow the use of these sources of supply is estimated at 25 billion pesos plus another 30 billion pesos to repair the hydraulic network.
According to various expert sources on the subject, it is very difficult to estimate how much water remains in the subsoil to be exploited. There are estimates that predict that by 2028 the CDMX and metropolitan area will already have a very significant shortage of the vital liquid. However, UNAM experts believe that the city could still have 30 to 40 years of constant supply left considering the current extraction of the aquifers, not without considering the terrible effects that the sinking would have on both the buildings and the network of pipes.
It is vitally important that local and federal governments take action on the matter urgently. More than 20 million people live in the Valley of Mexico, contributing approximately 17% of the national Gross Domestic Product. Needless to say, a population of this size without drinking water would completely collapse and with it all the economic activity it generates. In the next article we will talk about the impact that this can have on the real estate market (which is our specialty), however, in this installment we want to raise awareness of the great problem that is right infront of us and that is not currently on the agenda of the political parties. . The future of our children and the country is at stake. It is time to act. Time and water are running out.
