Abstract
A new sewer system is proposed in this paper. It is called E. S. S. that has been developed for reduction of urban storm runoff. ESS is the combination of many unit processes of infiltration and storage in the traditional sewer system. The served area with ESS has become 334 ha in Tokyo by the end of March in 1985. The quantitative effects of ESS are confirmed by practical measurements, and a total effectiveness of a basin wide area is evaluated by simulation model. Furthermore, operation and maintenance and the other problems of ESS are studied.
