Dam Breach Modeling and Inundation Mapping for Dabus Dam

No Thumbnail Available



Journal Title

Journal ISSN

Volume Title


Addis Ababa University


Dam breach pre-event analysis is vital to predict the dam breach parameters, outflow magnitude and its downstream nature of propagation. Setting out risk management, emergency action plans or evacuation planning system to protect both lives and materials during sudden dam failure phenomena and resulting flood waves is highly essential. Development of effective emergency action plan demands accurate prediction of inundation levels and the time of flood wave arrival at downstream critical locations. Dabus dam which will be constructed from rock fill material, within the Dabus Sub-basin of Abay Basin, has been selected for the study of dam breach analysis and flood inundation mapping. The paper focuses on overtopping and piping as the possible reasons of breach and identifies the inundation properties for bunches of breach parameters suggested by four different scholars. This has resulted in eight computer runs where halves are for piping and the rest halves for overtopping. HEC-RAS Ver5.0 is used to model the dam failure. HEC-GEORAS Ver 10.0 is used with ARC-Map 10.2.2 to extract basic geometric data for use in HEC-RAS. A 30m DEM is used as a terrain map to be used in ARC-Map. The four empirical methods of Dam breach study have resulted in peak flow values within a range of 14220m3/s and 8838m3/s during overtopping and 12891m3/s and 12717m3/s during piping. The result shows that the area found around left and right of the river which has been occupied by villages will be inundated partially. These results can be said more close when compared with each other. The process of gathering and preparing data, estimating breach parameters, creating an unsteady flow in HEC-RAS, dam breach parameters entry, performing a dam failure analysis



HEC-RAS, DEM, HEC-GeoRAS, Dam Failure, Breach, Dam Break Analysis, Scenario, Dabus Dam