Flood Mapping from Dam Break Due to Peak Inflow: A Coupled Rainfall–Runoff and Hydraulic Models Approach

In this study, we conducted flood mapping of a hypothetical dam break by coupling the Hydrologic Engineering Center’s Modeling System (HEC-HMS) and River Analysis (HEC-RAS) models under different return periods inflow. This study is presented as case on Kesem embankment in Ethiopia. Hourly hydrological meteorological data high-resolution land surface datasets were used to simulate design floods for piping failure with empirical breach methods. Based extreme inflows physical characteristics, was simulated two-dimensional, unsteady flow hydrodynamic model. As result, will remain safe up 50-year return-period inflows, but it breaks 100- 200-year downstream area. For 100-year peak inflow, 208 km2 area be inundated maximum depth 20 m duration 46 h. The inflow inundate 240 31 93 2D map provides satisfactory spatial temporal resolution evaluation affected facilities.