Flood Modeling and Simulation using iRIC: A Case Study of Kabul City

In Afghanistan, floods are common and measures must be taken to protect people and property from damage. There is, however, a lack of detailed observations and research on this subject in this area. Therefore, flood simulation models are needed to identify flood-prone areas. In this study, International River Interface Cooperative (iRIC) program that is river flow and riverbed variation analysis software with several solvers has been used. Nays2DFlood solver that simulates 2dimenstional plane flow has applied to a past flood in Kabul city. River discharge from two inflow points and averaged precipitation from three rain gauges at the time of flooding given as input to the model including DEM (Digital Elevation Model) data. The iRIC was confirmed as a 90-m grid digital elevation model to determine the position of streamlines correctly. However, the highest flood depth was overestimated because the 90-m grids were too coarse to detect the slight slope of the riverbed in some areas. Then the elevation of the riverbed modified using data acquired from Google Earth, and the simulation results improved. Moreover, it was found that river water rather than rainfall was the main cause of the flooding.