How Japanese engineers saved Tokyo suburbs from constant floods

Despite the fact that in Japan there are no large rivers, frequent sea cyclones, which bring large amounts of rain overnight, and the mountainous terrain cause floods. This problem is especially acute in coastal areas of the country with a high population density. One of them was the Tokyo area for many years, until the Japanese engineers were unable to build a unique protective system that forever solved the flood problem in the suburbs of the Japanese capital.

After long torrential rains, small rivers turned into turbulent and muddy streams that quickly overflowed the banks and flooded the city blocks located in the lowlands. Japanese engineers decided to build a reservoir for the discharge of flood waters, similar to those that operate in urban storm sewer systems. It should be noted that similar protective systems are quite common in Japan, which accumulate excess water during the spill of rivers. But most often they are built in the form of an open pit, which significantly reduces the cost and simplifies the construction process. But in the case of a suburb of Tokyo, busy with dense multi-storey buildings, this option did not fit, due to the lack of free space. Therefore, engineers decided to place the storage tank underground. The huge underground structure, the construction of which was carried out for 9 years, was completed in 2002.

The underground reservoir consists of several reservoirs that are connected to each other by tunnels with a diameter of more than 10 meters. Having gone through the labyrinth of underground tanks, the excess water is eventually pumped into the Edo River, with which the protection system is connected. This whole grandiose system holds about 160 thousand cubic meters. m of flood waters.

After completion of construction, this grandiose collector quickly became popular. During the lull between the floods, the interior is open to the public, which everyone is happy to use. In addition, the unusual atmosphere created by gigantic concrete columns and water that did not have time to dry made the underground collector a popular venue for filming.