Application of a rainfall-runoff model for regional-scale flood inundation mapping for the Langat River Basin

Rapid growth in recent decades has changed engineering concepts about the approach to controlling storm water in cities. Over the past years flood events have occurred more frequently in several countries in the tropics. In this study the behavior of Langat River in Malaysia was analyzed using the hydrodynamic modeling software (HEC-RAS) developed by the ‘Hydrologic Engineering Center, U.S. Army Corps of Engineers’, to simulate different water levels and flow rates corresponding to different return periods from the available database. The aim was to forecast peak flows, based on rainfall data and the maximum rate of precipitation in different return periods in storms of different duration. The maximum flows were obtained from the Automated Geospatial Watershed Assessment tool for the different return periods, and the peak flows from extreme rainfall were applied to HEC-RAS to simulate different water levels and flow rates corresponding to different return periods. The water level along the river and its tributaries could then be analyzed for different flow conditions.