the 3.3-km-long tunnel-shaped reservoir, which is 7.5 km in diameter That seems absurdly large. Then again, I suppose they want to avoid the question "what happens when it overflows?"
I believe it is 7.5 meters in diameter.
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Tokyo combats flood threats with second mammoth reservoir
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Re: Tokyo combats flood threats with second mammoth reservoir
#1211 CM of rain an hour? 7.5 km in diameter? Those looks like typos to me.
Re: Tokyo combats flood threats with second mammoth reservoir
#13[deleted]
Re: Tokyo combats flood threats with second mammoth reservoir
#14Re: Tokyo combats flood threats with second mammoth reservoir
#1511 CM of rain an hour? 7.5 km in diameter? Those looks like typos to me.
7.5km diameter is definitely a typo, it's supposed to be 7.5m.
11cm of rain per hour is not a typo. The Pacific Ocean contains more water than the rest of the oceans combined, and it can dump it wherever the hell it wants. East and Southeast Asia are particularly vulnerable because the trade winds blow hot moisture toward Asia (and away from the Americas). During the monsoon or when a big typhoon hits, some locations can get more than 10cm of rain per hour, although it's usually localized to a small area and only lasts a few hours.
Just a couple of weeks ago, a typhoon hit Jeju island in South Korea and dumped 1 meter of rain in 24 hours. That would be more than an entire year's worth of rain in most parts of Europe and North America, and would have been catastrophic if not for the highly porous volcanic geology of Jeju. The current record for South Korea is around 15cm per hour. Since Japan gets more typhoons than we do, I wouldn't be surprised if their record was even higher.
Re: Tokyo combats flood threats with second mammoth reservoir
#1611 CM of rain an hour? 7.5 km in diameter? Those looks like typos to me.
7.5km diameter is definitely a typo, it's supposed to be 7.5m. 11cm of rain per hour is not a typo. The Pacific Ocean contains more water than the rest of the oceans combined, and it can dump it wherever the hell it wants. East and Southeast Asia are particularly vulnerable because the trade winds blow hot moisture toward Asia (and away from the Americas). During the monsoon or when a big typhoon hits, some locations…
Localized precipitation can be unbelievable when a front stalls over an area, no major event like a typhoon / hurricane even required. The September 2013 floods in the front range of Colorado caused by a stalled front topped out at 9.6mm/hour on the worst day, with 430 mm total in 6 days - just under the average annual precipitation.
Re: Tokyo combats flood threats with second mammoth reservoir
#17Earlier quoted context omitted.
7.5km diameter is definitely a typo, it's supposed to be 7.5m. 11cm of rain per hour is not a typo. The Pacific Ocean contains more water than the rest of the oceans combined, and it can dump it wherever the hell it wants. East and Southeast Asia are particularly vulnerable because the trade winds blow hot moisture toward Asia (and away from the Americas). During the monsoon or when a big typhoon hits, some locations…
Localized precipitation can be unbelievable when a front stalls over an area, no major event like a typhoon / hurricane even required. The September 2013 floods in the front range of Colorado caused by a stalled front topped out at 9.6mm/hour on the worst day, with 430 mm total in 6 days - just under the average annual precipitation.
9.6mm/hr is an order of magnitude lower than what this Japanese reservoir is expected to handle. It would be considered heavy rain, but not at all unusual, for monsoon season in East Asia. It happens a few times every summer, so most cities in Japan and Korea are equipped to handle it just fine. If such events were more common in Colorado, they would have been better prepared, too.
Re: Tokyo combats flood threats with second mammoth reservoir
#18There are a few similar tunnels to this in the UK, including one around where I live. It's an interesting method, and probably one a lot of the US could benefit from too.
Re: Tokyo combats flood threats with second mammoth reservoir
#19Earlier quoted context omitted.
I believe it is 7.5 meters in diameter.
The picture in the article would seem to be a 7.5m tunnel, if the person in the picture is about 1.8m high. But this is Japan, so I'm going for 7.5km and the person is actually a 1.8km high Super Dimensional Fortress.
>But this is Japan, so I'm going for 7.5km and the person is actually a 1.8km high Super Dimensional Fortress.
I like this one better. Why doesn't their flood defence plan involve giant mecha to vaporise the water with lasers?
Re: Tokyo combats flood threats with second mammoth reservoir
#2011 CM of rain an hour? 7.5 km in diameter? Those looks like typos to me.
7.5km is clearly a typo.
11cm of rain isn't - this isn't that uncommon in extreme storm conditions.