EVALUATING PRECISION OF PLUVIAL FLOODING ANALYSIS AFFECTED BY DIFFERENCE INTERVAL OF RAINFALL EVENTS

Abstract

In recent years, damage caused by heavy rainfall for short period has been increasing in urban areas. In 2013 in Osaka, heavy rainfall—67mm per one hour and 27.5mm in 10 minutes—led to inundation above and below floor level and road inundation, which caused traffic disturbances. We focused on the center of Osaka, which has a large underground mall. Using 1D-2D urban flood analysis model, we predicted the overflow amount of pluvial floodwater, the expanse area and the onset of discharge, clarified the behavior of rainwater in the sewer system for five rainfall events. It is important that engineers should consider the adequate difference interval of rainfall events in analysis.