Tokyo and the rest of the world are suffering the consequences of climate change. This year has once again produced record-breaking temperatures. Many are unprepared for the heat, and heatstroke is on the rise. While the unbearable heat is the major focus, climate change is also causing record rain.
The rainy season in Japan is most commonly June through early July. However, that’s starting to change. The weather has become increasingly unpredictable. Torrential rains began in May, with Tokyo receiving record-breaking rainfall.
It hasn’t let up since. Torrential downpours and intense storms have been a hallmark of this summer. The air pressure changes have also caused an extended typhoon season, which can dump buckets of rain onto Tokyo in hours.
Preventative measures
The significant rainfall has caused a flurry of transportation issues. The unsafe weather conditions have delayed trains, planes, and buses. With overground transport in disarray, Tokyo’s extensive subway system has been a lifesaver.
The underground network of trains is the second most utilized in the world, serving millions daily. The stations are also part of a vast underground city of stores and restaurants, allowing passengers to stay underground while beating the rain and other inclement conditions.
While typically a reprieve from harsh weather, in the case of flooding subways with their enclosed spaces, minimal accessible exits, and excessive crowding are a recipe for disaster.
The risk of flooding is one that Tokyo’s two major subway providers, Tokyo Metro and Toei Subway, are acutely aware of. Recognizing the change in weather patterns the companies preemptively altered many features of the subway’s architecture over the years.
They’ve elevated the entrance and exits to above sidewalk level. Barriers to stop water from flowing in from street levels are installed at all entrances. In extreme cases watertight doors can close off the entryways completely, keeping potential flooding at bay. Street-level grates have anti-flood sensor devices installed to prevent water from entering.
Are the measures enough?
Despite their best efforts, current prevention methods have fallen short against the latest downpours. For the second year in a row, Tokyo subways have experienced flooding.
On Wednesday, August 21, 2024 “National Stadium Station”, “Ichagaya station”, and “flooding” were all trending on X (formerly Twitter). The pictures and the videos from the Toei and Tokyo Metro subway stations show large waves of water rushing down staircases and calf-deep water inside the stations. One user assured everyone that the images weren’t AI, as the shocking nature would lead to skepticism.
Train companies are aware that current measures designed to withstand 2 meters of flood waters are insufficient. They are currently working on barriers that can withstand six meters of water. They are also shoring up the waterproofing of said barriers and installing systems that would seal off corridors in stations, stopping widespread flooding in emergencies.
The subway companies have also started posting signage inside cars and stations telling people what to do in the case of flooding. The signs urge passengers to learn the risks of underground flooding, remain calm, and evacuate above ground.
While they may be good for bringing awareness that flooding can happen, the signs lack more detailed information. The recent floods illustrate that more thorough measures and signage need to be in place if subway companies want to live up to the motto of “Learn, Prevent, Save Lives”.
Underground anti-flood system
While preventing water from entering stations is an effective short-term solution, when preventing floods, the best defense is a strong offense. Tokyo has been tackling the issue head-on for decades, investing money into anti-flood infrastructure just out of sight.
Under the sprawling metropolis is a system of tunnels, holding tanks, and pumps designed to prevent major floods. Itโs a world-class system and attracts city planners from around the world.
The Metropolitan Area Outer Underground Discharge Channel (MAOUDC) was completed in 2006 after 13 years of continuous construction. Itโs the world’s largest water diversion system.
An extremely complex system of tanks and pumps, its main job is to pull water from overflowing smaller rivers and divert that water to the more accommodating Edo River. The tanks are massive, over 70 meters long, and the pumps are incredibly powerful. They could drain a large pool in the blink of an eye and can move 200 tons of water a second.
A race against time
Even with the current measures, government officials recognize that continued improvement is needed if Tokyo and its residents are to survive major flooding. Current weather predictions believe up to a 20% increase in rainfall is possible by 2050. That would overpower the current system.
With this in mind, Tokyo is in the midst of constructing Japan’s largest underwater regulating reservoir. Connecting the Kanda River and Shirako River reservoirs, the tunnel will span 5.4 kilometers between Nakano and Nerima wards. Construction is scheduled to be completed in 2025. Tokyo has 27 underground reservoir facilities now, with plans to increase this number by 2030.
Still, those in charge of disaster prevention are wary. Tokyo may be a shining example of a preemptive approach to flood management. But will it be able to outpace the devastating effects of climate change?
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Sources
ๅทจๅคงใชๆฑใๆ็ซใใใๅฐไธ็ฅๆฎฟใใ้ฆ้ฝๅๅค้ญๆพๆฐด่ทฏใฏ็ธใฎไธใงๆฎใใใๅฎใใๅผ็ใปๆฅๆฅ้จ. Sankei Shimbun
ใๅผท้ฑๅใใญใธใงใฏใใใ้ฝใๅทฅไบ็พๅ ดๅ ฌ้ใไบใค้ฃ็ตใๅฝๅ ๆๅคงใซใ๏ผๆฑไบฌ. Mainichi Shimbun
้ขจๆฐดๅฎณๅฏพ็ญ. Tokyo Metro
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