Earthen Dams Break Analysis, Flood Routing and Mapping using Mathematical Models and Geographic Information System (A Case Study: Alavian Dam)

Although a dam’s structure has an important role in suppressing floods and providing water for activities such as agriculture, human consumption, industrial use, electricity generation and pisciculture, its break has an immense damage and loss of life when it occurs. In order to reduce the damaging effects of the dam break on the downstream places, it is necessary to provide the flood hazard map. For this purpose, in the first step, the output breach hydrograph of the Alavian dam was computed by the BREACH model under the overtopping scenario. In the next step, the breach hydrograph was routed through the downstream of the river by using HEC-RAS model. Finally, the ArcGISsoftware was utilized to prepare the flood mapping. The results of the present study illustrated that the Alavian dam is breached with the time of failure of 46 min and the peak discharge of about 66000 m3/s. Furthermore, according to the flood hazard map, most of the downstream inundation zones due to Alavian failure dam have been considered as the high hazard area.