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Tuesday, Oct. 16, 2001
Forum eyes water management scenarios
Rainfall fluctuations mean government must prepare for drought and floods
By GARY TEGLER
KYOTO -- By 2025, it is predicted that nearly 5 billion people worldwide will face a severe shortage of water. A resource people take for granted may become as precious as diamonds or gold, according to a panel of experts who took part in a symposium last week in Kyoto.
The People's Forum on Water, a runup event to the 3rd World Water Forum to be held in March 2003 in Kyoto, was organized in this ancient capital by local nongovernmental organizations to raise public awareness of the pending crisis.
"Economic globalization and its effect on water management has a direct bearing on the lives of Japanese," said Hiroshi Kanda, a representative of ODA, an NGO and the main sponsor of the event.
"Wood, aluminum and food products imported into Japan, especially from Southeast Asia, impact on water usage in other countries. In Thailand, for example, mangrove forests have been cut down to create shrimp ponds," he said. "This in turn has adversely affected water resources in those regions.
"In a way, when Japanese people buy these products, they are importing water as well."
Unless something is done, ongoing droughts in Africa, Central Asia and China will cause massive population displacement on a scale not yet seen, Kanda said.
Japan's average annual precipitation of 1,800 mm -- about twice the world average -- means it has water management problems of a completely different nature, according to Satoru Kondo, an official from the Kinki office of the Land, Infrastructure and Transport Ministry.
Extreme variations in rainfall over the past 20 years, suspected to be caused by global warming, have resulted in unpredictable fluctuations in the water levels of rivers, Japan's main source of water for household and industrial use.
"Sometimes there is too much rain and other times there is too little," Kondo said. "The variation comes over a very short period of time.
"Japanese rivers, therefore, have characteristics that are difficult to control. They have steep gradients and are therefore swift-moving compared with rivers in Europe, he noted. "They flood more easily, and since 50 percent of the population lives in low-lying areas, this can have devastating effects."
Japan has used a two-pronged strategy to control its rivers. Nearly all of the nation's 108 "first-rank" rivers have had their embankments concreted to prevent flooding.
And, since the 1960s, the government has embarked on a dam-building spree to contain overflows and provide water in times of drought. According to Hideaki Oda, a former Construction Ministry official and secretary general of the 3rd World Water Forum, there are now some 3,000 dams in Japan.
"These dams have a capacity of 30 billion cu. meters," Oda said. "But if you look at the U.S., the Hoover Dam alone holds back 30 billion cu. meters, so the total capacity of all dams in Japan corresponds to only one in the U.S.
"This means we cannot expect a majority of our water to come from dams. If the water flow (of rivers) diminishes, we use water behind dams. But the water levels in these dams can drop rapidly, and during years of little rainfall, we are forced to ask people to cut back on their water usage."
Oda said that groundwater, though important for certain industries such as sake brewing, is not widely used in Japan.
In some rural areas, however, the use of groundwater -- and the subsequent drop in the water table -- caused land subsidence. Oda said this problem has largely been dealt with by strictly controlling the use of water from wells and underground springs.
In the Kansai region, the major water sources are Lake Biwa in Shiga Prefecture and the Yodo River Basin in Osaka Prefecture. Of the 20 million people living in the area, some 14 million rely on water from Lake Biwa, making it the most largely used water source in the country, said Yukiko Kada, a professor of environmental studies at Seika University.
Although detergent and phosphorous levels in certain parts of the lake are still unacceptable, Kada said she is more concerned about the effect a natural or man-made disaster may have on Biwa.
"If something happens at the (atomic) power plant in Wakasa, which is only 30 km away, it would be catastrophic," said Kada, noting she has begun to consider the effects a terrorist attack would have on the lake's water quality.
"The normal problems with lakes like Biwa, such as eutrophication (the overabundance of plant life that deprives animal life of oxygen) and water degradation, occur gradually. But the release of chemicals from an explosion at a nuclear power plant would come at once," she warned.
"For example, at the time of the earthquake in Kobe, the water pipes burst and people were fetching water right from the river and even from fountains in public parks."
One answer, Kada said, would be for local governments to maintain "neighborhood water."
"We have to keep wells, streams, rivers and springs not only for drinking but for children to play in, for dragonflies and small fish," she said. "This will be very important in the case of some natural disaster."
However, Kada noted that this would be somewhat difficult to achieve given the complicated system by which water use is regulated in Japan.
"River water is the responsibility of the Ministry of Land, Infrastructure and Transport. But water for agriculture and ponds falls under the Ministry of Agriculture, Forestry and Fisheries," Kada said.
"If you want to use groundwater for retailing, such as at restaurants, then you have to apply to the health ministry for special permission. If you want to take fish from the river, fishing rights are under the farm ministry, she said. "And, finally, industrial use is the responsibility of the Ministry of Economy, Trade and Industry."