Fahimeh Mokhtari - Ph.D. Candidate of Watershed Management Engineering at the University of Shahrekord, Chaharmahale Bakhtiari, Department of Range and Watershed Management, Shahrekord, Iran
Saeed Soltani Koupaei - Full Professor at the Isfahan University of Technology , Department of Range and Watershed Management, Isfahan, Iran
Afshin Honarbakhsh - Associate Professor at the University of Shahrekord, Chaharmahale Bakhtiari, Department of Range and Watershed Management, Shahrekord, Iran
Akbar Norouzi Shokrlu - Ph.D. Candidate of Watershed Management Engineering at the University of Shahrekord, Chaharmahale Bakhtiari, Department of Range and Watershed Management, Shahrekord, Iran

Floods, as one of the most catastrophic events among the wide variety of natural hazards, impose considerable damage to humans, infrastructure, and industrial and agricultural sites. To identify flooding-prone areas and having knowledge on occurrence probability or return period of flood events can be promising for planning and alleviation of damage caused by this natural phenomenon. This paper seeks to assess flood risk in the Ghamsar Watershed, then cross sections were plotted using a digital elevation model (DEM) and stream geometric data in the Hydrologic Engineering Center’s Geospatial Processing Data for River Analysis System (HEC-GeoRAS). The output was transferred to the Hydrologic Engineering Center’s River Analysis System (HEC-RAS) and flooding area with different return periods with data is created by an unstable simulation in the Ghamsar River.

Stable flow, unstable flow, HEC-GEO RAS ،HEC-RAS, Ghamsar watershed