Nov 302010

Thirty-one homes have been demolished due to structural damage resulting from subsidence in the colonia Benito Juárez. The subsidence, on 28 October 2010, occurred close to the Neza II garbage tip and affected more than 200 homes in total.

Temporary accommodation has been found for the families affected, who will have their rents of up to 2,000 pesos a month paid for the first six months. The compensation to be paid to the affected families from government coffers is still being decided.

Geologists and engineers from the Universidad Nacional Autónoma de Mexico (UNAM) y el Instituto Politécnico Nacional (IPN), are currently assessing the risks of alternative sites for rebuilding the 31 homes. Several areas of Nezahualcóyotl are known to be vulnerable to subsidence or to the sudden appearance of surface cracks (superficial faults).

The subsidence is presumed to have occurred because of the filtration of liquids from the Neza II tip through the subsoil, though precise details are still being investigated. To prevent further problems in the area, pipes are being installed to channel all liquid residues away from homes, and vents are being placed to allow the escape of gases emanating from within the garbage tip.

The three settlements of Nezahualcóyotl, Chimalhuacán and Los Reyes La Paz add about 1,000 tons of garbage daily to the Neza II tip. Authorities are now planning to close the tip completely by the end of November 2010.

Elsewhere in Nezahualcóyotl, the structural integrity of a shopping center and sports complex located near the Neza I tip are also being investigated.

The fact that subsidence occurs far more frequently in the eastern part of Mexico City (including Nezahualcóyotl) than elsewhere does not indicate that the solutions must be local. Ramón Aguirre, the director of Mexico City’s Water System (Sistema de Aguas de la Ciudad de México), has repeatedly emphasized the importance of looking at Mexico City’s potable water and drainage problems in the context of the entire metropolitan area (which extends well beyond the boundary of the Federal District). Aguirre fears that climate change and further over-exploitation of the aquifers, which Mexico City shares with the State of México, will only lead to more problems of water supply and more cases of subsidence.

Chapter 23 of Geo-Mexico: the geography and dynamics of modern Mexico looks at urban issues, problems and trends. To preview more parts of the book, click here and use’s “Look Inside” feature.

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