A Study on the Development of the Rain-based Urban Flood Forecasting Method with X-MP Radar in Toga River Basin

Abstract

This study developed efficient urban flood alert criteria nomograph that can be used without time delay. The reason for developing the nomograph is the characteristics of small urban watershed such as short concentration time by high impervious area and the localized heavy rainfall. The flood look-up table is based on rainfall information and shows possibility of flood occurrence by the location of average rainfall intensity and rainfall duration on look-up table. Moreover, we used the X-MP radar, which has finer spatial-temporal resolutions with higher accuracy than ever. To evaluate the applicability, we reproduced the flood using developed nomograph with observed gauge and radar rainfall for 9 events. We forecasted the flood occurrence using the nomograph with forecasted radar rainfall using short-term prediction method to secure the lead time. Through the results, we confirmed the developed nomogrpah and radar rainfall is useful for urban flood forecasting.