- MEXICO CITY -- Standing
in his office high above Latin America's largest city, the water board
operations chief Alejandro Martinez smiles as he considers one of the ironies
of Mexico City's development.
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- Five hundred years ago, it was a compact Aztec citadel
set in a broad highland lagoon. But today it is a vast metropolis sprawling
across a dried-up lake bed.
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- Mexico City's underlying aquifer is now collapsing at
a staggering rate beneath the streets. While Venice slips into the Adriatic
at a fraction of an inch each year, Mexico City is lurching downwards by
as much as a foot a year in some areas. Over the past century, it has dropped
30ft.
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- Chugging the equivalent of one Olympic-sized swimming
pool full of water every minute, the city's strained aquifers are dragging
much of the capital's rich heritage down with them, while the 20 million
residents face problems that include water-borne diseases, power outages
and the threat of riots.
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- The result of a head-on collision between booming demand
and finite resources, Mexico City provides a sneak preview of a situation
that the United Nations warns could become widespread in coming decades
as the world's mega-cities continue to grow unchecked and unplanned. Unesco
claims that up to seven billion people from 60 countries could suffer water
shortages by 2050.
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- Mr Martinez told The Independent: "The difficulties
that we are confronting today could be faced by other cities in the future
... We have to look for new and alternative technologies to find a solution
to the problem of producing water and avoid a crisis in the short term."
-
- Once a thriving city of "chinampas", or floating
gardens, linked to land by an elaborate system of causeways, the abundant
water of Lake Texcoco was gradually drained to make way for the colonial
capital after the Spanish Conquest in 1519. Despite rapid growth, the city
continued to meet its water needs in the 19th century from springs, shallow
wells and remaining surface water.
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- The first strains began to show with massive migration
in the 1940s; the capital began swallowing up one satellite town after
another as it grew by 7 per cent a year. Faced with shortfalls as the underlying
sand and clay aquifers failed to keep pace with demand, city authorities
tapped into two neighbouring river systems at a massive cost.
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- The city now has five pumping stations working around
the clock to draw water vertically three-quarters of a mile from the neighbouring
Cutzamala River basin and from the lower catchment area of the River Lerma.
Paying about $50,000 (£28,000) a day in water rights alone, the system
consumes the same amount of electricity as Puebla, a city of 1.3 million
people to the south-east.
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- Now comprising 350 neighbourhoods packed into a smog-wreathed
metropolitan area more than twice the size of greater London, the city
swills a massive 10.5 million gallons of water each day.
-
- Used by residentsand by water-intensive industries such
as beer brewing and soft-drink bottling, the ever-expanding metropolis's
supplies are again running short.
-
- In several shanty towns on the outskirts, a growing army
of bucket-wielding residents are forced to queue for water from a fleet
of tanker trucks that fan out across the city each day as authorities admit
to a growing shortfall. Mr. Martinez said: "In the past eight years,
the supply of water has remained constant, while the population has grown.
The network currently fails to reach about 2 per cent of the city, mostly
in outlying areas on higher ground."
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- In the leafy park surrounding the imposing Monument to
the Revolution, there is an old cast-iron well casing that has continued
to hold as the city around it has sunk. Once flush with street level, the
plain black pillar now stands 26ft high, serving as an unusual photograph
stop for slack-jawed tourists.
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- Inching through cross-town traffic to the Avenida de
la Reforma - a central thoroughfare that cuts through the city's upscale
business district - a towering column topped with a golden angel comes
into view. Built in the early 1900s to celebrate the centenary of the Mexican
War of Independence, 23 steps were recently added to reach its base as
the city fell away around it.
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- A short ride away in the north of the city, the yellow-domed
Basilica of Our Lady of Guadalupe is also in trouble. Built more than two
centuries ago to honour the patron saint of New Spain, the shrine tilted
so heavily beneath the weight of millions of pilgrims that it was declared
unsafe in the 1970s and a new basilica was built next to it. The listed
building now serves as a museum.
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- But collapsing heritage is just the tip of the iceberg.
Below street level, the ongoing subsidence is wreaking havoc with the water
distribution and drainage systems. The city's 8,300-mile network of water
pipes routinely fracture, losing up to 40 per cent of potable water supplies,
according to some estimates. The city's sewage used to drain away by gravity
towards a far-off outflow in the Gulf of Mexico but now needs to be first
pumped uphill before it can be drained.
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- © 2004 Independent Digital (UK) Ltd http://news.independent.co.uk/world/americas/story.jsp?story=516630
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