Monitoring and Analysis of Implemented Infiltration System over Past 20 Years

After implementation of the first rainwater infiltration system in Japan at the housing complex named "Akisima Tsutsujigaoka Heighs" in 1981, more than 20 years has been passed. Rainwater infiltration system is comprised of permeable connection box, permeable underground pipe, permeable U-shaped trench and permeable pavement. In order to evaluate the annual changes in the performance of these equipment for the runoff control, rainfall observation and discharge measurements have been conducted continuously for the districts with and without infiltration facilities since 1981. This paper presents the flood control effect by the infiltration system based on the observed data and runoff analysis by utilizing SHER (Similar Hydrological Element Response) Model for simulating the discharge hydrograph, and also describes the durability of the infiltration system over the period of 20 years. In addition to this, the effect on the groundwater recharge by the infiltration system is also evaluated by the SHER Model.