Two-dimensional modeling and zoning of urban flood in the north basin of Karaj city using HEC-RAS 2D

In many areas, urban flood and flood control system are not yet considered as an important issue in the design of the urban fabric and the problems caused by it are clearly seen at the city level. In order to control and manage urban flood, it is necessary to extract urban flood risk zones and analyze the vulnerability of urban infrastructure assets at risk. Flood risk assessment provides valuable information for flood risk management in order to assess vulnerability and face risk. Achieving this information requires the use of hydrological and hydraulic models and the analysis of damages to various urban facilities and uses. In this research, HEC-RAS hydraulic modeling has been used for two-dimensional simulation with the design return period (25 years) and flood depth and speed zoning for this return period. In this study, with accurate two-dimensional flood modeling, using the 1.5-meter height figure model, analyze and investigate the urban flood risk. The results of the research show that most of the areas that are facing floods and inundation are among the worn-out areas that have an older drainage network design, and the areas of Shahin Vila and Gohardasht are in an unsustainable condition compared to the other two areas and in contrast to the two areas Azimieh and Jahanshahr Karaj have better resilience than the other two regions.