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KOBE, Japan-- If you ask the man in charge of Kobe's water system if he has the most resilient system in the world, he gives a confident nod.
The great Hanshin-Awaji Earthquake of 1995 destroyed several water lines in Kobe, cutting water to the city for three days. As a result, entire neighborhoods burned to the ground because there was no water to put out the fires. Drinking water and water for toilets had to be trucked in for months.
Since then, Kobe's plant manager Hitoshi Araike, says the city has taken major steps to defend its water delivery system. First, it has installed 61 large storage tanks throughout the city. At the first sign of an earthquake, emergency isolation valves automatically close, so water stops flowing and stays in the tanks for use later.
Second, the city has installed a giant large capacity transmission main deep underground made of earthquake-resistant ductile cast iron. During normal times, it's a delivery main. But in an earthquake, it can store 59,000 cubic meters of water -- enough to supply the city's 1.3 million people with three liters per person for 12 days. You can't imagine how large an 8-foot diameter water main is. So I took a picture with it. I also stood in a cross cut piece. That's how big it is. It sits in an 11-foot diameter tunnel that's just over eight miles long.
Finally, the city has an ambitious plan to replace all of its aging pipelines to homes and businesses using either flexible (but tough) polyethylene pipes or ductile cast iron pipes with joints that slide like pistons but don't break. Araike is particularly excited about a pipe with an articulated joint -- sort of like an accordion bus that bends in the middle. This joint also bends and could straddle a fault line.
Replacing nearly 3,000 miles of water lines is a time-consuming process. The city is just 36% complete after 22 years. But when it's done, says Araike, "I expect zero disruption."
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