Three decades after the water drainage system for Mexico City (DF) was built, the structures are at their limits and there is a risk that many parts of the urban area could be flooded, newspaper El Universal quoted DF water authority (SACM) official Juan Carlos Guasch as saying.
Despite the fact that the most recent studies show there is no structural damage to the central pipeline of the "deep drainage" (Drenaje Profundo) system that empties the city of wastewaters and rainwater, if the system's capacity is exceeded, there could be serious consequences in much of the city.
"Every year, the Drenaje Profundo system reaches maximum operating levels of 170 cu m. If we add any more water, that capacity will be surpassed and we would have problems with flooding in various areas of the city," Guasch, operating director of the DF water authority SACM, was quoted as saying.
In order to avoid such problems, the city needs to build an eastern drain that would take wastewaters from that part of the DF urban area and thus prevent floods.
However, this project is not possible in the short term because it would require 6bn pesos (US$567mn) and four years to construct and water authorities simply do not have those funds available.
If the city is to avoid the collapse of its drainage systems, rapid investments are needed in infrastructure with much greater capacity, said Ernesto Domínguez Mora, sustainable development specialist at independent foundation Metrópoli 2025.
Mexico City requires the investment of 20bn-25bn pesos to build new drainage tunnels, pumping stations and water storage lagoons or it will be highly vulnerable to flooding, Domínguez claimed.
Although SACM is already carrying out various projects to improve the drainage of the valley in which Mexico City lies, the works will not provide a solution to the water problems in the city, said Guasch.
Mexico City's secondary drainage network, measuring some 10,000km in total, has already had its capacity surpassed because of the age and low capacity of the drains, said executive director of operations at SACM, Alejandro Martínez. It is this that is to blame for floods during the rainy season, added the official.
"We're talking about infrastructure that is 30, 40 or 50 years old. With the diameter with which [the drains] were designed, the size of the pipes, capacity has been exceeded and there are insufficient drains in certain neighborhoods," the official was quoted as saying.
"If there is very heavy rain, the drains could be saturated and there could be momentary floods, but at the same time the central drain of the Drenaje Profundo could be empty," he added.
The solution is the total renovation of the city's drainage system, but this is financially impossible to achieve, said Martínez.