Based on the Water Resources Development Promotion Law, the seven river systems (Tone river, Arakawa River, Toyokawa River, Kiso River, Yodogawa River, Yoshino River and Chikugo River), where water supply had become necessary in response to industrial development and population increase in urban areas, have been designated as water resources development river systems. In each of the designated river systems, the water resources development basic plan (the basic plan) has been made, and comprehensive development and rational use of water resources are advanced.
Districts receiving water supply from the designated river systems (the basic plan area) only account for 17% of the national land area; however, about 50 % of the total population and industrial activities of Japan are concentrated in the seven river systems.
The following are supposed to be included in the basic plan. The basic plans are determined by the Cabinet, in consultation with related ministries, by hearing opinions of related prefectual governors and the National Land Development Council.
As a result of constructing facilities based on the basic plans, approximate 380 m3/s of volume of water has been thus far developed and available. Approximate 325 m3/s of volume of water for domestic and industrial use was also developed in accordance with the basic plans, which is equivalent to about 50% of total volume of water developed newly in the country. Besides, these facilities have become important lifelines for major urban areas where a population and industrial activities are concentrated.
We currently reconsider the basic plans from the following points of view, having receiving the report of the studies and planning subcommittee of the water resources development council in December 2000.
The basic plan in Yoshino river system was revised in February 2002.
Subcommittees, which have been set up for designated river systems in the water resources development committee, have started reconsidering the remaining six river systems (five basic plans). We are currently reviewing forecasts of water demand and supply in relating prefectures. And with the result of it, we also intend to revise the remaining basic plans of each river system. Thereafter we will continue reconsidering and revising the basic plans, taking into account economic and social transition in future.