The increasing demand to healthy water has lead to rapid progress in the field of dam engineering and construction of different dams all over the world. Although the structural analysis and design of dams have been improved significantly in recent years and the dam construction imposes exorbitant costs, but dam break is an inevitable phenomena in dam engineering field. Destructive floods that happen every year all around the world are great hazards for stability of dams. Since new fields in dam engineering such as; passive defense, flood warning systems and risk management are raised recent years, hence studying the behavior of the flood caused by the breach of dam, conducting preventive measures and predicting possible consequences have interested researchers and engineers more than ever. There are different numerical/experimental investigations performed on hydrodynamic behavior of dam break flood in straight canals based on 1-D modeling. But less has done based on two dimensional analysis of flood behavior due to more time consuming and more expensive solutions. In this research the two dimensional SVE equations (MIKEFLOOD software package) are used to study the flood behavior in meandering rivers with consecutive bends. In order to verify the validity of model predictions, the dam break has been investigated experimentally by sudden opening of a flood gate in a flat rectangular channel. The wave progress and its characteristics have been traced or measured and compared with the results of 1-D model. Also, to investigate the dam break phenomena in meandering rivers under real conditions, the Zayande-Rood dam and river data are used as the case study. The dam break phenomena are modeled in 110 kilometers of river length based on 1-D modeling and in the first 16.5 kilometers of river length based on 2-D modeling. Results showed that considering the presence of bends and their consecution have significant effects in decreasing the maximum flood discharge and yields to considerable time delay in the flood movement towards the downstream. Keywords: Dam Break; Hydrodynamic Modeling, Meandering River, Zayande-Rood River.
