Dam Breach Modelling and Downstream Risk Analysis (For Arjo-Dedessa Dam)

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Date

2015-12

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Addis Ababa University

Abstract

Analysis and simulation of embankment dam breach events and the resulting floods are critical to differentiating and reducing threats due to potential dam failures. Development of effective emergency action plans requires accurate prediction of inundation levels and the time of flood wave arrival at downstream critical locations. The Hydrologic Engineering Center’s River Analysis System (HEC-RAS) can be to develop a dam failure model. HEC-GeoRAS was used to extract geometric information from a Digital Elevation Model (DEM) and then imported into HEC-RAS 4.1 where one dimensional Unsteady-flow simulation of the dam breach performed. The simulation results were mapped using the GIS extension tool HEC-GeoRAS on ArcMap. Inundation mapping of water surface profile results from dam failure models provides a level of the flood hazard and provides insight for emergency action plan. The process for gathering and preparing data, estimating breach parameters, creating an unsteady-flow model in HEC-RAS, entry of dam breach parameters, performing a dam failure analysis for two dam failure scenarios, mapping of the flood inundation and emergency action plan are discussed in this paper. Key Words: Dam Breach, Modelling, DEM, HEC-GeoRAS, HEC-RAS, Hydrograph, Inundation

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Keywords

Dam Breach, Modelling, DEM, HEC-GeoRAS, HEC-RAS, Hydrograph, Inundation

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