Friday, May 22, 2009

Founded on water, dying of thirst -- Mexico City

Homero Aridjis in the Guardian (UK): … Tenochtitlan, Albrecht Durer's ideal city, was crisscrossed by canals and streets of water, and the flourishing of its economy depended on water. A system of aqueducts brought spring water from Chapultepec and other hills surrounding the island-city, which was connected to the mainland by three causeways. … The Spaniards continued to rely on spring water until the mid-19th century, when they began to exploit groundwater. Only one river remains today in Mexico City, the Magdalena; all the others had been turned into underground sewers.

Mexico City is a prime example of unsustainable use of water resources. A huge percentage of waste and rain water literally goes down the drain, flowing through the deep drainage system, hailed in its time as an engineering marvel, to empty into distant rivers and the Gulf of Mexico. The Valley of Mexico, some 2,200 metres above sea level, is surrounded by high mountains. One fifth of the country's population lives and works here, in one of the world's largest and most populous cities.

About 70% of the city's water comes from the valley's aquifers. To make up the deficit, Mexico City is drinking up two rivers: the Lerma and the Cutzamala. A substantial fraction of the energy generated in the country is needed to pump the water from 120 kilometres away and up 1,200 metres to the city. As much as 40% of the water is lost to leaks in the aging distribution network and at points of use. Much of the infrastructure was built 80 years ago. Meanwhile downtown Mexico City is sinking, as the aquifers are drained.

…This spring millions of people were left without water when the city government turned off the taps to overhaul the aging system and conserve reserves until the rainy season replenishes the supply. Government officials and city residents are equally pessimistic. Mexico City, founded on water, may one day die of thirst.

Mexico City view, 1890. Scanned from A Photographic Trip Around the World, John W. Illiff & Co., Chicago, 1892.

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