This has been an abnormal summer, weather-wise. The almost nonexistent rainy season left the level of dams and reservoirs in the Tone, Arakawa and Tama river systems that serve as Tokyo's water supply have fallen enough for a "yellow warning light" to be flashed, reports Yukan Fuji (Aug 16). In anticipation of troubles ahead, the water supply from the Tone River system has already been reduced by 10%.
According to the website updated daily by the Bureau of Waterworks, Tokyo Metropolitan Government, rainfall from Typhoon No. 7, which on Aug 16-17 skirted the Pacific Coast, had little effect on reservoir levels.
Should the shortage become severe enough to require further cuts in supply, Yukan Fuji warns it may mean it won't be possible to flush toilets in homes and office buildings, and major water consumers, such as hospitals and small manufacturing businesses, will be forced to curtail operations.
On Aug 5, the eight dams of the Tonegawa system, Tokyo main source of water, were down to 59% of capacity and by August 12, the largest, the Yagisawa dam, had declined to 43%. Japan's Meteorological Agency blames the climate abnormalities on the presence of the La Nina phenomenon, a cooling of the Pacific surface off the coast of Peru, which is part of the Southern Oscillation climate pattern that alternates with El Nino.
Without sufficient rainfall, the supply from the reservoirs will be incrementally reduced.
Taikan Oki, a professor at the University of Tokyo's Institute of Industrial Science, notes that should the supply be cut by 20%, water pressure may also decline, reducing the gush from faucets to a trickle.
When supply cuts fall to 40%, it's effectively a water outage.
"When the flow stops and toilets stop flushing, people will have to refill their toilet tanks from jerry cans of water, and I suppose they will also start hoarding bottled drinking water," Oki was quoted as saying. "Swimming pools at schools and other places will also be forced to close."
"When the flow is reduced by 70%, it's possible that tap water will only be available for 8 hours a day, usually at times that coincide with preparation of breakfast and supper," Oki continues. "Manufacturing businesses will be vulnerable, with companies like steel producers, which need water to cool the molten metal for example, seriously affected. It will also become more difficult for food and beverage businesses that rely on water for food preparations."
The most serious of all, Oki warns Yukan Fuji readers, would be hospitals, where patients on treatment requiring large quantities of water, such as those undergoing kidney dialysis, "would probably have to be transferred to hospitals in another part of the country."
A similar situation happened before in 1964 -- the year of the first Tokyo Olympiad -- when the lack of rainfall led to a record-setting water shorage. That summer households were only able to obtain half their normal water supply. Echoing the sense of panic felt by the public, the media coined the word "Tokyo sabaku" (the Tokyo desert), and the 1964 shortage became so severe that barber shops closed their doors and thieves stole water from the spigots of others.
Compared with 1964, Tokyo has greatly bolstered its water supply system. Still, at this time of year, the reservoirs that serve Kanto are typically at around 90% of their full capacity. But if more rain doesn't fall soon, some people may begin asking if the "Tokyo desert" is about to make a reappearance.© Japan Today