Every year, people's lives and property are in danger by flood all over the world. Development of cities and villages in riversides and floodplains without doing necessary studies and considering hydrologic and dynamic conditions of rivers and watershed upstream increases the risk of flood and the resulting losses. For this reason, estimation of the damages and losses caused by flood and flood zoning is important in floodplain management. In this study, the losses caused by flood in Ghorood watershed basin have been calculated using HEC-FIA software, which is a new model (Sep., 2012) used for the estimation of the losses and the impacts caused by flood. Ghorood watershed is one of the sub watershed of Daryache Namak baisi in Kashan City. Ghorood watershed affected by flood and many floods have occurred in This watershed. Among the recent floods in Ghorood is the one occurred in 2007 which caused many losses. In order to estimate the losses and impact caused by flood, several software packages have been used among which are HEC-Geo RAS, HEC-RAS AND HEC-FIA. The data required for HEC-RAS such as cross sections, prepared using DEM, which is provided in HEC-Geo RAS software. These data with discharge in different return periods and flood hydrograph occurred has been transferred to HEC-RAS software for the simulation of steady flow and unsteady flow. The discharge in different return periods has been calculated from flood frequency analysis of maximum instantaneous discharges. HEC-DSS file and height of flooding are the output of HEC-RAS software. Height of flooding data has been transferred to HEC-Geo RAS for preparing flood inundation map. The flood inundation maps show that the rate of flooding is increased by increasing return periods. Flood inundation map, HEC-DSS file and agricultural, building and human losses data, entered to HEC-FIA model, for the estimation of losses on agricultural crops and buildings. The results of this research are flood inundation maps and agricultural, building and human losses have been estimated using HEC-FIA model. An area about 0.85 hectares of farming lands has been flooded. The agricultural losses on three crops included plum, walnut and apple have been estimated about 350 million Rials and 24 buildings have been damaged by flood. Key words : Flood zoning, HEC-Geo RAS, HEC-RAS, HEC-DSS, HEC-FIA, Impacts Assessment, Ghohrood Watershed.
