2000 年 31 巻 3 号 p. 15-38
The quality of water in Tokyo Bay has been deteriorating since the early times. National government and local government have implemented many policies for the improvement of the water quality. But the water quality of the environmental standard point in Tokyo Bay has not improved sufficiently. We have to make an effort for the improvement of water quality. At present, there is no policy to ensure the practical use of the budget of prefecture or city integratedly for the improvement of the water quality.
The pollution discharged from Edogawa River and Arakawa River catchment area (Edogawa River, Nakagawa River, Arakawa River and Shingashigawa River catchment area) constitute a little more than half of the pollution discharged from Tokyo Bay catchment area. If we can improve the pollution discharged effectively from these areas, the water quality in Tokyo Bay will improve considerably. And among these catchment area, Saitama Prefecture is a upper and Tokyo metropolitan is considerably down. If we can improve the water quality not only Tokyo Bay but also the rivers more than the present policies, the residents of these catchment area can agree to ensure to the practical use of the budget of the prefecture or city for the other prefecture or cities.
The eutrophication in Tokyo Bay is due to pollution (nitrogen, phosphorus and COD) discharged from socio-economic activities and land use of the catchment area. But our purpose is to reduce pollution without deteriorating remarkably the socioeconomic activity level and proper land use in this area.
In this study, we formulate a model which describes socio-economic activities, land use and the load of pollution (nitrogen, phosphorus and COD) and suggest effective policies in order to reduce pollution. We simulate the model which can promote a sustainable development of Tokyo Bay catchment area from the year 1997 to 2004.