The Great Drainage Canal of the Valley of Mexico: a project that took almost three and a half centuries to be completed

Due to a flood in 1555, the decision was made to create a drainage system to avoid future problems in the city. A project was created that went through several setbacks until it was inaugurated in 1900 by Porfirio Díaz. Learn about the history of the Gran Canal de Desagüe, an engineering work that is part of the system that today frees Mexico City from sewage.

On March 17, 1900, the then President of the Republic, Porfirio Díaz, inaugurated the works of the Great Drainage Canal of the Valley of Mexico, whose immediate operation we can observe thanks to one of Charles B. Waite's photographs, taken just a year after its formal start-up (image 1). Waite, taken barely a year after the formal start of its operation.

Thus, the objective that had been proposed since the early years of the Colony to drain the rivers of the Valley of Mexico, where the city of Tenochtitlan was settled, materialized. The aim was to put an end to the flooding that the city suffered, especially during the rainy season, which also caused the land to sink.

As a result of the great flood of 1555 in the capital of New Spain, the idea of completely draining the Valley of Mexico emerged for the first time. This first project was entrusted to Francisco Gudiel, who, in addition to proposing the general drainage of the valley, also proposed the use of its waters for irrigation and navigation. But the plan did not work as expected and in later years the floods continued, as did the many ideas to consolidate a drainage system capable of redirecting the rivers that crossed the city.

It was not until the middle of the 19th century that a more solid foundation was laid for a drainage project of this magnitude. This was proposed by the engineer Francisco de Garay, director of Aguas del Valle, who proposed opening a large canal from Lake Texcoco to the northwest region of Tequixquiac. These works would be completed with other canals to the south and east which, in addition to assisting in drainage, were considered as potential waterways for commerce.

However, it took ten years after the presentation of the project for de Garay to formally begin work on the officially named Gran Canal del Desagüe. The works began in the last stretch of the resistance against the French intervention and the empire of Maximilian of Habsburg. Hence, the defeat of the empire meant the suspension of the works and the revival of the works became difficult due to the economic and political situation of the country.

This new project included the construction of a canal, a tunnel, and an outlet section. By 1894 the first part of the tunnel was completed, but for some reason, the Mexican company did not finish the work. For this reason, a new contract was signed with private capital, this time with the English firm S. Pearson & Son, preserved in the Communications and Public Works collection of the National General Archive.

The document stipulates in 12 points and five transitory articles the execution of the excavation works pending from kilometers 0 to 9 and from kilometer 47 to the entrance of the Tequixquiac tunnel, at a depth of 10 meters from the definitive draught so that the waters of the canal would flow down.

On May 26 of the same year, the presidential decree declared valid the contract signed between the Mexican government, on behalf of Manuel González Cosío, Secretary of Communications and Public Works, and the English company S. Pearson & Son, was made official.

Six years later, on March 17, 1900, the 47-kilometer general drainage project was inaugurated, starting in San Lazaro and ending at the Zumpango Lagoon, State of Mexico. An image taken by photographer Charles B. Waite a few years later, allows us to appreciate what the work looked like at that time.

A sewage network was connected to this drainage system that connected homes, hospitals, public buildings, and markets. In this way, waste and sewage would be disposed of more efficiently and hygienically and would be complemented by the first drinking water supply system, designed by engineer Manuel Marroquín, which was built between 1905 and 1908. The new system required constant monitoring to assess its performance, so the country's Hydrographic Commission was in charge of drawing profiles of the water levels in the different sections.

Thus, since 1900, this system has functioned to avoid the magnitude of the floods that occurred in the capital. However, today there are new challenges for a city like ours, which continues to suffer from sporadic flooding, rethinking the historical challenge of an urban structure located in the middle of a valley and what was once a lake.

Multiple factors explain the persistence or resurgence of the problem, but thanks to operations that are more committed to maintenance and restructuring, it has been possible to contain it, even if not successfully, but in a way that seems to be more effective. Experiences such as these connect us with the work of generations to build a niche to prosper in this corner of Mexican territory and the AGN is witness to these titanic efforts.