Determining of Flood Zones Using Hec-Georas Software in Gis Environment

Abstract

Iran because of its particular climate and in respect of being flood prone is seventh country in the world and sustains lots of damages every year. Reducing of crisis impacts requires integrating of various data including topography, roads, buildings and urban facilities. In this order GIS along with hydraulic models are key tools that provide suitable response and analysis and also possibilities for determining flood zones and safe places. In this paper, first all of required information layers were designed using GIS and secondary programs such as HEC-GeoRAS and ArcHydro and after creating spatial database of parameters including river route, cross-sections, longitude slope of river, banks and discharge amount imported them into the hydraulic model of HEC_RAS. After running the model the obtained results including flood zone, depth of water flow were sent again to the GIS environment and in shape of a information layer placed upon a land use map and by 3D simulation of the region different land use condition in flood occurrence time were determined. Since the result of this research further determining zone, water depth, different land use condition could also determine safe places using different functions in GIS environment. Furthermore since the results obtained from hydraulic model run are including flood prone zone and also the flow depth at each region we could provide an accurate estimation of damage due to flood with different return periods.