Evaluation of the Effects and the Programming of 'Water Conservation Plan' (WCP) for Total Water Resources Management in Tokyo

Abstract

In major cities, rapid urbanization due to population and economic growth generally cause increase in water demand. Furthermore, lifestyle change encourages per capita water consumption to increase. The government tends to have policies that support increasing capacity to response to rising demand but this requires huge funding and several other problems such as opposition by environmentalist. To overcome these problems, water demand should decrease especially by reducing per capita water consumption through water conservation. On such basis, this paper focuses on the evaluation of 'Water Conservation Plan' (WCP) implemented by Tokyo Metropolitan Government (TMG). Tokyo faced tight water resources problem during the high economic growth period around 1960s. However, by incorporating both supply and demand side control measures in WCP, Tokyo became advanced in water resources management and now has excess water supply to meet the demands. Tokyo managed to reduce the per capita water consumption to about 171 L/p/d or more in 30 years. But due to pushing-up factors, which contributed 89.5 L/p/d of increment, the actual reduction was equivalent to 81 L/p/d or 19% reduction rate. Total supply side measures are almost equal to demand side measures where the weightage is 44:56 respectively. Hence, the authors analyze the effects of WCP from the viewpoint of supply and demand side control.