Tokyo combats flood threats with second mammoth reservoir
japantimes.co.jp
japantimes.co.jp
Um, it's more than a quarry. Chicago is 3/4 through a sixty year project to install more than 100 miles of underground tunnels and reservoirs which will hold 66 million cubic meters of water when finished in 2029 (or thereabouts). The quarry is a temporary reservoir.
"Tokyo is becoming increasingly reliant on this unique-to-Japan solution as more typhoons hit the country each year"
as the US has seen no increase in hurricanes, and the last decade in particular has been remarkably lacking in hurricanes.
That seems absurdly large. Then again, I suppose they want to avoid the question "what happens when it overflows?"
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?
It must be hard to build it in middle of metropolis, but this is hardly 'mammoth'.
This massive reservoir could be about 50 by 50 by 50 meters. Or 10 meters deep, and 120 meters square. Which is in a lot of water, in a sense.
But compared to the Hoover Dam, which is 2,600,000 cu of concrete (and about about 300 million times the capacity of the Japanese reservoir, if you're including Lake Mead) it's not very big.
Note - I might have made a huge mistake somewhere here. It's hard to tell when you start cubing things, because intuition starts breaking down.
However, following the 2008 crisis, the government followed a strategy of immediate spending reduction (as opposed to US stimulus spend).
While mega projects such as this were still funded, the budget for environmental management was reduced by ~30% accounting for inflation. This impacted river and drainage channel maintenance, greatly increasing damage inevitable from bad weather.
The cost of the 2012 floods post cuts was £1bn, compared to a cost of 0.5bn from worse weather before the cuts in 2009 (similar rainfall accompanied by strong winds as well).This is about 30% more than the total saving from budget cuts.
The interesting thing is, I have not yet seen anyone in the press draw a connection. The locals know, that the floods rose from ditches and rivers that were not dredged. I've not seen the broader picture mentioned in the UK press once.
Maybe no one cares, because drainage is boring, and doesn't do anything when it isn't desperately needed. There are a lot of things like that.
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.
Just yesterday, Hiroshima set a new three-hour rainfall record of 217.5mm. The peak was just over 100mm/hr. Massive landslides killed over 40 people. No typhoon was involved.
11cm of rain isn't - this isn't that uncommon in extreme storm conditions.
Put me down as another person unimpressed with it's capacity - for a city the size of Tokyo, I expected it to be much larger. Perhaps it's only for one or two of the special wards? It's certainly a beautiful looking tunnel. But I can't help but wonder if they spent too much money/time on perfecting it.
No thank you.