It's the rainy season now in Mexico. Between May and September, on most late afternoons, thick clouds roll into Mexico City's mountain-ringed valley. The skies darken and then an amazing downpour ensues. Despite the rainfall, for five months of the year, many of the metropolitan area's more than 20 million residents don't have enough water to drink. Nearly all that rainwater runs off the streets and highways into the city's massive drainage system built to stave off perennial flooding. Drinking water increasingly comes from a vast aquifer under the metropolis. And as that water table drops, the city sinks. So why put a capital city more than 7,000 feet above sea level, in a mountain-ringed valley, that fills like a plugged-up bathtub when it rains? "It's a historic mistake the city has had to pay for more than 500 years," says Ramón Aguirre Díaz, who has run Mexico City's municipal water system for more than a decade.
The Mexico City Metropolitan Cathedral in Zócalo Plaza has had to undergo repeated repairs. It is among the many structures in the Mexican capital that are sinking.
The ancient Aztecs first picked the spot. They built their city atop the huge lakes that filled this valley, leaving the natural freshwater supply intact around them. The city flooded back then too, but the Aztecs, probably the last civilization to properly manage this watershed, built a system of dikes to control the problem. The "historic mistake" kicked in around the 1600s, when Hernándo Cortés and his band of conquerors arrived. To make room for their expanding empire, over a few hundred years, they slowly but surely drained all the valley's lakes. By the 20th century, long after Mexico's independence from Spain, the fresh surface water was mostly gone and the hunt for new sources had taken over.
Hundreds of miles of pipes now bring in about 30 percent of the city's water needs from faraway rivers and lakes. The rest comes from the valley's vast underground aquifer. Today, Aguirre says, twice as much water is pumped out as is put back in. "We are depleting volumes of water that took hundreds, thousands of years to store. Sooner or later it will run out," he says.
Marco Marquez, 52, keeps storage containers filled with water on his patio. The tap runs dry on a regular basis, but he needs clean water especially for his fruit business.
When exactly that is, no one really knows. But for those living in the poorer eastern stretches of the city, like 52-year-old Marco Marquez, it feels like now. "Look," he says, as he spins his water tap. "Nothing — not even a drop." During the rainy season, Marquez gets about an hour of water a day. His little patio is crammed with different sizes of storage containers filled with water. During the dry season, he can go two, even three months without water. He says sometimes the government will send in a water tanker truck, known as a
pipa, which literally means pipe. "The quality of the water the government provides is really bad quality, it's disgusting," he says. "You can only use it to flush the toilets or wash the sidewalk." Marquez says sometimes he and some neighbors pool their money to buy a private
pipa with water from better wells. He needs clean water to run his fresh fruit stand. He has named the small storefront, run out of a street-facing room in his house, the Oasis.
A large crack cuts through this Mexico City street. Half of the street is lower than the other half, one of many signs this metropolis is sinking.
The city's underground pipes, half of which are at least 60 years old, fail at an alarming rate. It could take at least 50 years, and hundreds of millions of dollars, to replace all the old, ruptured pipes, according to one official estimate. That means the water tankers are in high demand. Twenty-two-year-old Juan Flores stands on top of a 2,600-gallon tanker. He guides a huge hose connected to a pipe pumping water directly out of the aquifer into the truck. "I'll take this to fill up tanks at schools and hospitals around this district," which borders Mexico City's airport, he says. In many ways sending trucks all over the sprawling capital is a more efficient system than the city's pipes, which are so prone to breaks and leaks that nearly 40 percent of the drinking water running through them is just wasted,
according to a government study in 2010.
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