|Water for Urban Areas (UNU, 2000, 243 p.)|
|2. Water management in Metropolitan Tokyo|
|The present situation|
In 1973, the "oil shock" created economic confusion throughout the world. Japan, having been seriously affected, has since then employed energy conservation as a state policy.
In January 1973, in order to balance water demand and also to control it, the Tokyo Waterworks Bureau publicly announced its "Policy to Control Water Demand," which was a forerunner for cities across Japan. At that time, despite the increase in water demand in Tokyo, water resource developments were not progressing according to plan, owing to popular movements against dam construction. Future water supply shortages were therefore anticipated.
For 80 years, with the constant increase in public water demand, the bureau had been planning and executing water resources development projects. This new policy was a great turning point in Tokyo's water demand planning. Furthermore, in Japan the supply of drinking water is a financially independent business within each city. Considering the fact that controlling demand meant less revenue, this was a drastic change of policy in the Waterworks Bureau.
At about the same time, a "water conservation conscious society" was proposed by the water administration of the state government. Such a policy was becoming popular all over Japan under the influence of cities such as Tokyo where water consumption was high.
In 1987, learning a lesson from the water shortages of that year, a Round-table Committee for Creating a Water Conservation-Conscious Society was formed within the Waterworks Bureau. The committee's report states the need to make urban society aware of the need for water conservation through the reinforcement of conventional water conservation systems and the philosophy of water recycling. Since then, the Waterworks Bureau has been actively promoting public relations activities to develop awareness of water conservation among citizens in their daily lives. It has also been requesting manufacturers to develop fixtures such as faucets, toilets, and laundry machines that conserve water.
Concerning the promotion of efficiency in water use, since 1984 there have been individual building recycling, district recycling, and large area recycling. Treated sewage and industrial water have begun to be utilized as their water resources.
As part of its leakage preventive measures, the Bureau makes it a rule to carry out repair work on the day that a surface leak is found. Where the leak is underground, the potential leakage volume is assessed by the minimum flow measurement method, and leaks are located with electronic leak detectors, correlation-type leak detectors, etc. (all performed at night-time). As a result, the leakage rate was reduced to 16.1 per cent in 1977 and to below 10 per cent in 1995 (as shown in table 2.2 above). The target is to bring the rate down to 7 per cent by the beginning of the twenty-first century. To prevent leaks, ductile metal and stainless steel are being used for water distribution pipes.