Like the Philippines, Japan is also frequented by typhoons. To keep some key parts of the country from being submerged by floodwater caused by these typhoons, which by the way grow stronger and more frequent each year, it developed an engineering marvel called the Kasukabe Underground Flood Protection Tank.
Completed in 2006, it has been successful so far as a flood protection facility for eastern Saitama Prefecture and parts of north east Tokyo, namely, Adachi, Katsushika and Edogawa wards. The massive tunnel, which construction began in 1992, is located in the outskirts of Kasukabe City. The entire project cost $ 2.2 billion, and is used around seven times a year.
According to JapanVisitor.com, the Kasukabe Underground Flood Protection Tank works through five collection silos that collect the excess water via a 6.3km long central tunnel from the minor rivers. These silos are approximately 70m high and 30m wide. The water is then shot through the 10m wide underground water tunnel running 50m below Highway 16 (a major thoroughfare) towards the surge tank facility in Kasukabe, the website wrote.
After the collection during typhoons or heavy rainfall, the water is then let out into Edogawa River through pumps, later released into Toko Bay. It is being discharged at a rate of equivalent to discharging a 25-meter swimming pool every second, with the power of a jumbo-jet engine.
With this facility, official research has declared that it has saved 148 billion yen in disaster clean-up costs so far, or equivalent to $1.4 trillion.
Meanwhile, Japan Times reported that a flood facility similar to this reservoir in Kasukabe is being built in Osaka Prefecture, at a cost of $3.5 billion with target completion date in 2044.
Tours are available for the Kasukabe Underground Protection Tank. And certainly, when Filipinos, particularly engineers avail of this service, we can only wonder and think, “When will the Philippines ever have this kind of flood protection project?”