Background of Innovative Technologies in Japan

In highly urbanized areas, it is almost impossible to make use of traditional older technologies to conquer the urban drainage problems of today. Therefore, various kinds of advanced innovative technologies have been developed and applied in every crowded city of Japan. This paper gives analyses and comments on the development of BMPs through 20 years of experience with infiltration practices as an example of developing new technologies in Japan. In Japan, BMP means infiltration and storage. Infiltration and storage has been the regular technology up to now. Many cities have been adopting the technology. However, it has not gone mainstream and has not become routine because urban drainage management is carried out against various kinds of social and economic backgrounds. In this paper, the experiences with problems and solutions are introduced and analyzed.