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<\/a><\/p>\nWhat happened and why did it attract attention?<\/p>\n
Urban expansion has reduced permeable areas, altered natural watercourses, and increased the risk of flooding during heavy rainfall.<\/p>\n
Over time, the traditional drainage model has ceased to keep pace with the reality of a super-dense metropolis, where water finds increasingly less space to drain.<\/p>\n
The solution was to move part of the flood control underground, with tunnels and reservoirs capable of receiving water from multiple points simultaneously.<\/p>\n
Concrete columns tens of meters high support the main chamber of the underground system, creating a monumental space where water is controlled before flowing through tunnels that prevent flooding on the surface.<\/p>\n
How does the G Cans Project work beneath the city?<\/p>\n
The best-known system of this strategy is the G Cans Project<\/strong>, officially called Metropolitan Area Outer Underground Discharge Channel<\/strong>.<\/p>\nThe structure includes 5 wells<\/strong> enormous, each reaching 70 meters deep<\/strong>, interconnected by tunnels carved into the rock.<\/p>\nThese tunnels add up to more than 6 kilometers<\/strong> and channel the water to a main control chamber, where the flow is stabilized before discharge.<\/p>\nThe central point of the system is an underground chamber with 177 meters long<\/strong>, supported by large concrete columns.<\/p>\nWhen the rain intensifies, the water enters through the wells and flows through the tunnels to this space, which functions as a transition and control area.<\/p>\n
From there, the flow depends on high-power pumps<\/strong> which push the water to a safe destination, reducing the risk of it returning to the surface.<\/p>\nAn underground chamber with large concrete columns is part of a system that receives extreme volumes of water, controls the flow of diverted rivers, and helps prevent surface flooding during periods of heavy rain.<\/p>\n
What changes in practice for those who live in a metropolis like Tokyo?<\/p>\n
During heavy rain events, the difference is evident in real life: fewer blocked streets, a lower chance of transportation disruption, and a reduction in the immediate impact on vulnerable areas.<\/p>\n
The city now has an extra layer of protection that is not visible in everyday life, but comes into play when the volume of water rises too quickly.<\/p>\n
This model also requires constant operation and maintenance, because its functioning during critical moments depends on the reliability of the entire system.<\/p>\n
Why can’t the system stop, even for a short time?<\/p>\n
The entire logic of this structure stems from a simple principle: the water needs to keep moving so it doesn’t return to the surface.<\/p>\n
When the volume increases rapidly, the ability to capture, direct, and expel this flow becomes crucial to prevent chain flooding.<\/p>\n
Therefore, the system functions like a continuous machine, which depends on constant monitoring and an immediate response whenever weather conditions worsen.<\/p>\n
Tokyo has adopted an extreme solution to continue existing in an increasingly impenetrable territory.<\/p>\n
With 5 wells<\/strong>, 70 meters deep<\/strong>, more than 6 kilometers<\/strong> of tunnels and a chamber of 177 meters<\/strong>The city transformed invisible rivers into essential infrastructure to keep urban life functioning even on the most critical days.<\/p>\n","protected":false},"excerpt":{"rendered":"Published 26\/12\/2025 \u00e0s 10:27 Most of Tokyo follows the normal rhythm of a megacity, but beneath the streets…\n","protected":false},"author":2,"featured_media":253564,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[269],"tags":[131573,18,440,19,17,133],"class_list":{"0":"post-253563","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-environment","8":"tag-cidade","9":"tag-eire","10":"tag-environment","11":"tag-ie","12":"tag-ireland","13":"tag-science"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/115790016897823696","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/253563","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=253563"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/253563\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/253564"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=253563"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=253563"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=253563"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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<\/p>\n![\"\"](\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/12\/Design-sem-nome-2-11-1095x730.jpg\"\/)
Concrete columns tens of meters high support the main chamber of the underground system, creating a monumental space where water is controlled before flowing through tunnels that prevent flooding on the surface.<\/p>\n![\"\"](\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/12\/Design-sem-nome-1-14.jpg\"\/)
An underground chamber with large concrete columns is part of a system that receives extreme volumes of water, controls the flow of diverted rivers, and helps prevent surface flooding during periods of heavy rain.<\/p>\n