The entire Mexico City basin faces a water crisis that could make the infamous smog seem trivial by comparison.
The problem rests with the depletion of an ancient aquifer that supplies the region's 20 million inhabitants with water."This mega-city is unsustainable," says environmentalist Marisa Mazari of the National University (UNAM). "There are few ecosystems in the world so far from being self-sufficient as the basin of Mexico."
Because it pumps 70 percent of its daily consumption from an underground aquifer that took millions of years to accumulate, the city is sinking into the ground at a rate of 2.4-2.8 inches a year. The ancient center of what was once the Aztec capital of Tenochtitlan has sunk by up to 26 feet this century, and in some outlying areas the annual rate of subsidence is as much as 8 inches.
Architect Jorge Legorreta describes the resulting compression and dehydration of the underlying clay - a lakebed in pre-Conquest times - as the No. 1 danger facing the city. He believes deterioration of the subsoil would magnify the effects of an earthquake like the devastating 1985 tremor that killed up to 20,000.
Then there's the question of contamination. More than 90 percent of liquid industrial waste, for example, is discharged untreated into the sewer system, while one-fifth of the population has no household sewage service.
Built in a valley surrounded by high mountains, Mexico City is "condemned to live in its own waste," says Joel Simon, author of a book on the country's environment. He points to studies which suggest that the supposedly "impermeable" clays protecting the aquifer in fact allow contaminants into the groundwater.
The danger is highlighted by the experience of neighboring Hidalgo state, where 140,000 acres of agricultural land are irrigated with waste water from Mexico City, 95 percent of it untreated. High levels of heavy metals have been found in vegetables grown on the land despite a theoretical ban on food crops.
At the heart of the impending crisis is the irresponsible use of a precious resource by a government virtually unchallenged politically for most of its 66 years in power. The Institutional Revolutionary Party encouraged the growth of a city that holds one-fifth of the country's population and accounts for one-third of its energy consumption, much of it required simply to pump in water.
Per capita daily water use by the city's inhabitants - at 70 gallons - is among the highest in the world. Up to one-third of pumped water is lost, much of it through cracks in pipes.
City authorities, currently a department of the federal government, acknowledge that there's a serious problem. But critics say there are neither long-term plans nor money to implement them, a problem exacerbated by the economic crisis triggered by the peso collapse of December 1994.
The economic crisis, and the fact that the first direct elections to the city government are planned for next year, also have interfered with moves to reduce the water authority's massive budget deficit.
Fearful of a political backlash, the government has several times postponed the introduction of proper metering. Four foreign companies, brought in to help implement the new metering project, have been severely hampered by cutbacks and bureaucratic delays.
The rainy season is about to begin, but the water will mostly go down storm drains.
(Distributed by Scripps Howard News Service.)