This gallery is part of a National Geographic News series on global water issues.
A worker walks through a pipe at a construction site near Tokyo Metropolitan Bureau of Water Works’ Nagasawa Water Purification Plant.
A nuclear emergency in earthquake and tsunami-struck Japan is shining a light on the importance of water in fueling the planet: Nuclear production takes copious amounts of H2O. But before the crisis, Japan was making huge strides in water filtration technology and water supply and sewage management systems built to withstand earthquakes.
(Read more about energy’s water footprint in National Geographic Freshwater Fellow Sandra Postel’s latest blog post: “This World Water Day, Think -- Energy,” and see “Japan Reactor Crisis: Satellite Pictures Reveal Damage.”)
The Clinton Foundation’s Climate Initiative sustainable cities program has named Tokyo “the world leader in stopping water leakage.”
The Bureau of Waterworks serves nearly 12 million people in Tokyo, and, according to the Clinton Foundation, it has nearly halved the amount of water lost to leaking pipes in the past decade—from 39.6 billion gallons (150 million cubic meters) a year to 17.9 billion gallons (68 million cubic meters) a year. That’s about enough to supply Tokyo with water for 14 days and New York City for 15 days.
Tokyo’s water managers have made an intensive effort to replace or repair pipes as soon as a leak is detected. Aging pipes are often replaced with more earthquake-resistant magnesium-reinforced cast iron. And a highly evolved computerized detection system monitors the city’s water supply 24 hours a day.
This year’s annual World Water Day, sponsored by the United Nations (UN), is dedicated to discussion about “Water for Cities” and the challenges of providing an increasing urban population, especially in the developing world, with adequate water and sanitation services.
With more than half the world’s populations in urban areas, many flocking there just recently, water supply often presents huge obstacles. One of every four city residents worldwide, or 789 million people, live without the type of clean and safe sanitation services sometimes taken for granted in the developed world. And, according to the UN, 27 percent of people living in cities do not have water piped into their homes, meaning they are often finding water through illegal, unregulated, and polluted sources.