Dam breach is rare event in which dam fails releasing impounded water to downstream regions. Dam breach has low probability of occurrence but carries high risk of destruction. Dudhkoshi Storage Hydroelectric Project concrete faced rock fill dam (CFRD) was studied for dam breach under overtopping and piping failure modes. Dam breach simulation and flood propagation study is vital for identifying and minimizing the risks associated with breach flood. Two scenarios namely base-case scenario with average value of dam breach parameters and worst-case scenario with value of dam breach parameters resulting in maximum output. Local and global sensitivity analysis are performed for four dam breach parameters (dam breach width, breach formation time, weir coefficient, trigger failure elevation). Sensitivity analysis is performed for two river profile. Sensitivity on peak discharge, peak velocity, arrival time and water surface elevation were evaluated. ArcGIS, HEC-RAS and OriginPro 2022b are used for dam breach analysis. Overtopping failure was found to be critical as compared to piping mode.