Ecoducto Río La Piedad

Mexico City’s troubled relation with water is fairly well-known: from the Aztec/Mexica city of Tenochtitlán which was based on islands found on a large series of brackish lakes, to the modern metropolis stuck between cycles of drought and flooding. Among draining aquifers causing soil subsidence and lost canals, it may be easy to assume that the rivers that once fed the lake system are gone too. However, some of these still run in Mexico City, intubated and well out of sight, often combined with urban sewage and drainage systems.

La Piedad is one these rivers, a victim of the city’s growth. It eventually became polluted, which, along with flooding risks, led to its intubation. Above it is the Miguel Alemán Viaduct, named after the man who was president of Mexico when the viaduct was inaugurated in 1950. Probably starting with Paris's Promenade Plantée, which opened in 1993, the turn of the 21st century saw cities from New York to Bangkok turning functionalist or abandoned pieces of urban infrastructure into linear parks. Mexico City’s own take would be the Ecoducto, opened in 2017. This park was built atop the structure housing the pipes in which La Piedad River flows.

Río La Piedad’s Ecoduct features a large number of tanks with aquatic plants and fed with water from the river running below. This water is often measured to test their potential to remove pollutants out of the river. The plant-lined walkways of this linear park run in the middle of this section of the Miguel Alemán Viaduct, with several information boards explaining the ongoing experiments.

Along with the existing park, there have been several proposals to restore the open river, similar to other recovery projects like Cheonggyecheon in Seoul and the L.A. River. The Ecoduct's success, as of late 2024, seems limited, as water reports often show that the cleaning abilities of the plants are slow and the boards are mostly faded, likely making the open river a very long-term future ideal.