Water for people.pdf - WHO Thailand Digital Repository

4 8 8 / P I L O T C A S E S T U D I E S : A F O C U S O N R E A L - W O R L D E X A M P L E SGreater Tokyo, Japanknown to carry severe health risks), which exceeded environmentalstandards in three out of eighty-seven measurement points(Environmental Bureau of the Tokyo Metropolitan Government, 2000).A survey in 1999 of non-native species in Japan’s rivers yielded thefollowing results: fish represented 6.1 percent, benthos 2.2 percent,plants 11.0 percent, birds 2.4 percent, amphibians 5.3 percent, reptiles7.7 percent, mammals 18.4 percent and insects 0.7 percent(Foundation for Riverfront Improvement and Restoration, 1999). Blackbass and blue gill, which are non-native fish, were found in 40 percentand 30 percent of dams, respectively (Water Resources EnvironmentTechnology Center, 2001).Challenges to Life and Well-BeingTo meet the needs and demands of the large human and industrialactivities, vast water resources and policy implementation arenecessary. The following is a summary of water uses in the region.The water volumes given below represent the total sevenprefectures, not the five river basins.Water use in industry and citiesIn 1998, the total volume of water used in Greater Tokyo was163.5 bm 3 . Thirty-four percent of this water is used for households,Figure 22.3: Rate of ground subsidence in cm/year14 percent for industrial activities and 52 percent for agriculturalactivities. The volume of water used in agriculture in Tokyo region isrelatively low compared to the 66 percent used country-wide. Thevolume of water for households has slightly increased in recent years,while that of water used for agriculture has not changed. As for thevolume of water used in industry, there is only a very slight increase,the result of massive water recycling (Water Resources Department,MLIT, 2001).In Greater Tokyo, 44 percent of total water resources are usedduring normal years, and 66 percent during drought years. Thispercentage is twice that of the whole country (Water ResourcesDepartment, MLIT, 2001).Groundwater resources make up 22.8 percent of total water useinland, and 13.1 percent in seaside areas. Some 45 percent ofhouseholds and industries, considerably more than agricultures, relyon groundwater. So as to prevent land subsidence, groundwaterwithdrawals have been regulated. Limits on withdrawals ofgroundwater come in the form of two laws: the Industrial WaterLaw, which targets groundwater used for industrial purposes, andthe Law Concerning the Regulation of Pumping-up of Groundwaterfor Use in Buildings, which targets groundwater used for coolingand other building-related purposes. Groundwater withdrawal in thenorthern part of the Kanto plain has decreased from 13.1 bm 3 in1985 to 9.6 bm 3 in 1999 (Water Resources Department, MLIT,2001). As a result, the rate of land subsidence has stabilized (seefigure 22.3).Ground subsidence (cm)0 Minami Uonuma (Yokawa, Muika-machi, Niigata Prefecture)Chikugo/Saga plain (Yokoto, Shiroishi-cho, Saga Prefecture)Kanto plain (Higashi Owa, Washimiya-cho, Saitawa Prefecture)-100Nobi plain (Hakkei, Nagashima-cho, Mie Prefecture)Niigata plain (Sakai, city of Niigata, Niigata Prefecture)-200Osaka plain (Hyakushhima, Nishi Yodokawa-ku, Osaka city)Kanto plain (Kameido 7 Chome, Koto-ku, Tokyo)-300-400-50019001910192019301940195019601970198019902000There has been a dramatic increase in ground subsidence in the Greater Tokyo region in the past century. Since the 1980s, this subsidence has stabilized. The Kanto plain hassuffered particularly significant ground subsidence, and is now over 4 metres lower than it was in 1900.Source: Water Resources Department, MLIT, 2001.