Comparison of Using DEM(10m) and DEM(50m) to Simulate Flood Hydrograph (Case Study: Kasilian Watershed)

Rivers morphology and geometry are one of the main factors about time of concentration and pick discharge in watershed. Digital Elevation Model (DEM) is a technique to make morphology and geometry. DEM accuracy is very important to simulate flood hydrograph. This study has been done using Geographic Information System (Arc View/ HEC-GeoHMS) and HEC-HMS software in Kasilian watershed. In the first Step, hydrologic model of Kasilian watershed has been calibrated and evaluated using Digital Elevation Model(50 m) and 4 rain fall and flood events. Then, this model has been performed using DEM (10m) and evaluated flood event. The result of these hydrologic models was compared in terms of simulating flood hydrograph. The result showed that DEM accuracy is very important for simulating flood hydrograph.