Tokyo bolsters defences for storms that would dwarf Hurricane Sandy

Tokyo, the world's most populated city, is building defences for a once-in-200-years flood that could dwarf the damage Hurricane Sandy wrought on the US east coast.

Japan's capital could face 33 trillion yen (HK$2.5 trillion) in damage should the banks break on the Arakawa River that bisects Tokyo, according to government estimates. That is more than five times the US$60.2 billion aid package provided after Sandy's assault on the US in October.

"Japan hasn't prepared enough," said Toru Sueoka, president of the Japanese Geotechnical Society, an organisation of engineers, consultants and researchers. "Weather patterns have changed and we are getting unusual conditions. We need upgrades or else our cities won't be able to cope with floods."

Japan plans to spend 1 trillion yen on nationwide disaster prevention, including strengthening levies, in the fiscal year that started on April 1, according to the transport ministry.

Should the Arakawa break its banks, about 2,000 people in Tokyo may lose their lives and 860,000 will be stranded, according to the government. Water would flood subway and regular train lines, crippling 97 stations.

One of Tokyo's largest wards, Edogawa City, which is sandwiched between the Arakawa and Edogawa rivers, predicted it would cost 1.7 trillion yen to strengthen and rebuild the banks to prevent breaching during a flood, said Naomasa Tachihara, director of Edogawa's department of public works planning.