Enhancing a Distributed Rainfall Intensity for Flood Analysis within a GIS Framework in an Urban Area (Kajang Flood)

Abstract

The town of Kajang has experienced major flood events in previous decades since 1970s. Due to Eastern and Western Monsoon seasons in Malaysia, Kajang has potential to face with number of flood events. One of the critical elements in flood analysis is rainfall distribution. Therefore, flood studies need to have an optimum cognition of rainfall distribution as main input. In this study, HEC GeoHMS model was used in GIS (Geographic Information System) for Sungai Jeluh catchment (Kajang) due to estimation (visualization) of distributed rainfall in Kajang. In comparison with conventional methods, which they produced rainfall in lumped mode (e.g. Thiessen's polygon), HEC GeoHMS visualized and tabulate a full distribution of rainfall for each small part (pixel of map) in a case study. HEC GeoHMS model for Sungai Jeluh has been set up by feeding high resolution of spatial and temporal resolution data (precipitation). Result of this study shows that rainfall by high intensity is distributed near urban area (downtown) in comparison with upstream which involved with less rainfall intensity.