Daniel, Fikreselassie (PhD)Bedilu, Dejene2020-11-252023-11-112020-11-252023-11-112020-09http://etd.aau.edu.et/handle/12345678/23554Flooding is one of the most common, wide-reaching, and destructive natural perils, affecting, on average, approximately 250 million people around the world each year. It is also common in Ethiopia during the rainy season between June and September. Most of the flood disasters in Oromia are associated with rivers that overflow and burst their banks succeeding heavy rains and inundated lowlands. Flooding of the upper basin and tributaries of Awash River affected 14 peasant’s associations (Pas) in Illu, Sebeta Awas, and Ejere woredas of southwest Shewa zone. The flood was reported to have affected a total of 14,790 people out of which 2,052 people were displaced and inundate along the river banks in lowland plains. The objective of the study is to quantify and estimate the damage of flooding on the economy in the Illu Woreda Teji Area using the HEC-FDA model. Adopting HEC-GeoHMS Arc-GIS extension physical characteristics of a catchment is obtained from the study area digital elevation model. Using the study area rainfall/meteorological data/ HEC-HMS model computes peak flow for different return periods near the outlet of the river catchment. Flood plain mapping near the Teji River was generated depend on the peak flow of the river for different return periods by the HECRAS model, Arc-GIS to the special data processing as well as HEC-GeoRAS to link ArcGIS with HEC-RAS. Depending on the HEC-RAS result hydraulic model, applying the HEC-FDA model, numerically flood damages are estimated. The flood plain area across Teji River generated for 2, 5, 10, 25, 50, 100, 200 as well as 500 return periods were 308, 422, 459, 507, 535, 574, 598 as well as 622 ha consecutively. In the end, flood damage costs were estimated by the HEC-FDA model. From the study, the main output is expected annual damage (EAD). That is EAD is estimated to be 2,962,832.59$(Two Million Nine Hundred Sixty-Two Thousand Eight Hundred Thirty-Two Point Five Nine Dollar). Additionally using HEC-FDA model by assigning a levee the economic damage is reduced to 403.43$, and levee is proposed for flood plain management.en-USFlood DamageTeji RiverHEC-HMS HEC-RASHEC-GEORASHECFDAEADThesis