Record-breaking temperatures and scant rainfall have prompted authorities across the nation to cut water intake, with the government warning that water shortages in the Kanto, Chubu and Shikoku areas could match those during Japan’s worst recorded drought eight years ago.

In 1994, some 15 million people throughout Japan were hit by tap water suspensions, forcing people to line up with buckets at emergency water supply vehicles.

The Health, Labor and Welfare Ministry predicts that water shortages could be extremely severe from late August to early September.

It is also warning residents against outbreaks of food poisoning that could arise from a deterioration in water quality.

At 10 a.m. Friday, Tokyo and five neighboring prefectures began cutting their water intake by 10 percent. Areas along seven other major rivers in Japan have adopted similar measures.

The recent lack of precipitation has led to severely diminished reserves at eight reservoirs on the upper Tone River, according to the Land, Transport and Infrastructure Ministry.

It is the first time water restrictions involving the Tone River system have been imposed since the August 1996 drought.

The restrictions affect Tokyo, Saitama, Ibaraki, Tochigi, Gunma and Chiba prefectures, according to the land ministry.

The ministry revealed that the restrictions will be expanded during the latter half of next week should there be a further decrease in water levels due to a rainfall shortage.

Roughly 174.87 million tons of water had been impounded as of Friday behind the eight dams — including the Yagisawa Dam in Minakami, Gunma Prefecture — the ministry said.

It added that the reservoirs in question are filled to just 51 percent of their capacity, down from the usual summer level of 81 percent.

The Yagisawa reservoir, the largest of the eight, has seen its level drop to 30 percent, or about 34.42 million tons, with its water level some 22 meters below capacity.

With water intake restrictions in place, local governments will limit the amount of water flowing into water purification plants, although this will not directly affect households in the form of reduced tap pressure, it said.

The Tone River, which flows through the Kanto region, is the second-longest river in Japan and has the largest drainage basin.

It is an important source for the drinking and industrial water needs of the Tokyo metropolitan area.

Rainmakers fired up

As local authorities across the Kanto region cut their water intake, the Tokyo Metropolitan Government dusted off decades-old rainmaking devices Friday on the border between Tokyo and Yamanashi Prefecture.

It has been five years since the metro government has attempted to artificially induce rain.

Whether due to the machines or not, 42 mm of rain was logged in Kosuge, Yamanashi Prefecture, between 2 p.m. and 4 p.m. This was much-awaited at nearby Ogochi Dam in Okutama in western Tokyo, the only dam in the capital that supplies drinking water.

The rainmaker consists of a heater and chimney in which an acetone solution of silver iodide is vaporized and released into the atmosphere. The silver iodide particles, said to pose no health risk, serve as a catalyst for forming raindrops.

The metro government has set up these devices in four locations in Tokyo and nearby Yamanashi Prefecture since 1966. The devices were last used in 1996, when a similar dry spell forced local authorities to limit water intake.

“It’s an epoch-making achievement by Tokyo’s epoch-making experiments,” Gov. Shintaro Ishihara told a regular news conference after he was informed of Friday’s rainfall.

However, the effectiveness of the devices remains unconfirmed.

“I believe the device triggered the rainfall, but it could have rained without them,” one Tokyo official admitted, adding that past results vary too much to establish a pattern.

The Meteorological Agency forecast clouds and a 20 percent chance of rain for some areas of Tokyo on Friday afternoon.

In any case, the officials said the devices only work when rain clouds are present. They can’t make rain under clear skies nor can they boost the volume of precipitation when it is already raining.

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