Flood forecasting is an important mechanism to prevent and manage the consequences of floodrndamage problem on agricultural areas. This study focuses on assessment of Sedie river floodingrnproblem by preparing flood inundation map for different return periods. Different modelsrnincluding hydraulic model HEC Ras, hydrological model HEC HMS with integration of ArcGIS,rnHEC GEOHMS and Ras Mapper tools used for conducting this study. Primary data, surveyed riverrncross section and secondary dataâ€™s such as rainfall, stream flow, DEM, Land use / land cover andrnSoil type dataâ€™s collected and used for the study. Totally around 8 years of observed flow data 5rnyears (1996-2000) for calibration and 3 years (2001-2003) for validation used. After the analysisrnof the data it was found that HEC HMS calibration and validation result was good and thernperformance of the model checked with the coefficient of determination and Nash-Sutcliffe withrngood result of 0.84 and 0.83 for calibration, 0.74 and 0.73 for validation respectively. Due to thernunavailability of observed water level and rating curves in the study area the HEC RAS modelrncalibration and validation result compared qualitatively and relatively good result obtained. Therncalibrated manning roughness for the left and right bank obtained 0.035 and 0.025 for the mainrnchannel of the river. The flood inundation map prepared by using Ras Mapper tool and differentrnflood inundation map results for different return periods obtained. The flood inundation map showsrnthat for especially 50yr and 100yr return periods the flood damages 177.22 ha and 280.78 harnfarming areas respectively. Therefore in order to mitigate this damages structural and nonstructuralrnmeasuresrnrecommendedrndependingrnupon thernsevere ofrndamagernatrneachrnstations.