RELIABILITY OF FLOOD CONTROL AT THE INCOMPLETE SECTION OF RIVER IMPROVEMENT OF THE ZENPUKUJI SMALL TO MEDIUM-SIZED URBAN RIVER

Abstract

 Reliability of flood control at incomplete section of river improvement against 50mm/hr rainfall in the Zenpukuji River in Tokyo, the typical urbanized area, are investigated using Urban Storage Function (USF) model. USF model is one of the rainfall-runoff analysis models considering urban runoff process. The results show that overtopping of river occurs approximately once two years in the objective points at present. Then, inundation damage risks increase when rainfall reaches 30mm in 60 minutes or 20mm in 30 minutes. Lastly, utilization of forecasted rainfall for evacuation is desired because overtopping of river can occur soon after such a heavy rainfall was observed.