Water Scarcity - The Ripple Effect: The Fate of Freshwater in the Twenty-First Century - page 103

his mayorship, progress on the tunnel has remained steady, as has his worry about the
city's water supply.
The pressure to finish Tunnel No. 3 as quickly as possible is high. Beginning in 2004,
the hogs tunneled five days a week, in three shifts a day, in “maximum effort,” said Ted
Dowey. In any twenty-four-hour period, about 165 men were in Tunnel No. 3, shuttling
between work sites by six diesel locomotives.
As my tour of Tunnel No. 3 came to an end, Dowey explained that about six more
years of work lay ahead: the DEP would have to line the tunnel with concrete, sterilize
it so that it can carry drinking water, hook it up to many trunk lines, it it with instru-
ments and sensors, and connect it to the command center under Van Cortlandt Park.
(By 2010, the excavation of Stage 2 was complete, and the hogs were working one shift
per day, mostly in the Distribution Chamber.)
We rode the elevator cage back up Shaft 26B to the surface and emerged, blinking
in the sharp light and cold air. As we stepped out of the cage, a fresh crew of sandhogs
trooped aboard. There was some jovial shouting, one man made a quick sign of the
cross, the cage door slammed shut, and within minutes the men had disappeared down
the giant hole.
THE URBANIZATION OF WATER
While the fragility of its water system is a pressing concern to New York, other large cit-
ies face even greater and more immediate hydrological challenges.
In 2000, the world had 18 “megacities,” with populations of 5 million to 10 million
(depending on different definitions), or more. In 2007, 336 cities worldwide had popu-
lations of 1 million or more. According to the UN, in 2008, for the irst time in history ,
more people lived in urban areas than in rural ones.
As of 2010, China alone had at least 43 cities with populations greater than 1 million;
by 2025, according to ForeignPolicy,that number will grow to 221. Seventy percent of
Chinese will live in cities of at least 1 million by then, and 44 Chinese cities will have
populations of at least 4 million.
Yet some of the world's biggest cities have already suffered unprecedented water
shortages. In 2007 and 2008, Barcelona, Spain, and Melbourne, Australia, faced drought
emergencies. Cities in Brazil and South Africa, nations already rife with social unrest,
suffered numerous brownouts because reservoir levels were too low for hydroelectric
turbines to spin properly. Mexico City, having drawn down the large aquifer beneath its
streets, began to subside: sidewalks caved in, walls buckled, sinkholes appeared and oc-
casionally swallowed cars and buildings.