Introduction

The reservoir dams of Mashampa, Marash and Taham are constructed across the Qezel Ozan, ? and Sarmasaqlu rivers respectively, and the reservoir dams of Glabar, Bloubin, Kineh Vars and Talvar are constructed across the Sajas-Roud, Abharr and Talvar rivers respectively, in Zanjan province. According to the international standards, dam break studies are required for dams that will cause significant damage if they break. Therefore, considering the location of these dams in rural and urban areas and the presence of significant agricultural lands at the foot of the dams, dam failure studies and creation of an emergency action plans for these dams are essential. From the perspective of design, construction, operation and maintenance, all efforts are made to ensure that no dam breaks, except in special cases, such as when the dam is built for military purposes or in the case of structures such as fuse plugs that are expected to break when necessary. But a number of dams breaking occurs because of the following reasons:  

• Earthquake
  • Landslide
  • Severe flooding
  • Facility failure
  • Upstream dam breaking
  • Foundation failure
  • Piping and Seepage
  • Structural instability
  • Wave erosion
  • Sabotage/military attack

  The outputs of these studies mainly indicate the main characteristics of the flood, such as the depth and speed of the water and the determination of the flooded areas at different times; Moreover, the time it takes for the peak flood discharge ,caused by dam breaking, to reach different parts of the river downstream of the dam, as well as the cause of dam breaking and the reduction in the water level in the dam reservoir are other issues that have been addressed in this study. An important part of these outputs is presented in the form of flood maps, and the other part includes tables that describe the main characteristics of the flood. These maps and tables will be the main criteria for creating an emergency action plan.

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