This study presented dam breach analysis & inundation map for Melka Wakena Dam. Melka Wakena Dam is an earth-rock fill dam with 42m height and 2000m long. The dam was designed to produce Hydropower of 153 MW. In this study, the Melka Wakena Dam breaching outflow hydrographs and downstream flood propagations were simulated by applying computer programs to recognize the possible relationships among the peak flows, dam breach parameters and downstream river parameter.rnDam breach analysis & inundation map involved with reservoir routing and river routing techniques. The key inputs required in the flows routing processes include time to dam failure in hours (TFH), side slope of dam breach (SS), shape of opening, downstream channel geometries, Manning roughness coefficients and inflows to reservoir. The reservoir components of routing were performed applying HEC-RAS computer program. Similarly, the HEC-RAS computer program was applied to conduct unsteady flow routing through the river components of the testing waterways and produced various peak flows for given conditions at specified downstream reach stations.rnThe maximum breach discharge resulted from HEC-RAS model was 36,527.15m3/s which results in overtopping the dam by 18cm and the maximum breach discharge results for piping 32,627.70m3/s. The influences of dam breach and river parameters on maximum breaching outflow discharges were analyzed at the dam site and downstream stations. Dam breach analysis & inundation map analyses results showed that the maximum discharge and downstream routing. The breach discharge for overtopping maximum than piping.rnKey Words: - Dam Break, Inundation Map, Dam Breach Parameters, HEC-RAS.