Investigating of the flood risk in MeshginShahr city Using WMS and HEC-RAS Models

In the last decade, the occurrence of destructive floods has increased due to the increase in temperature, the expansion of urbanization and the change in the characteristics of the catchment area, along with the change of land use and improper use of land. The purpose of this research is to investigate the flood of Meshkin Shahr using WMS and HEC-RAS models. In this research, using the WMS model, modeling of the maximum flood and determination of the flood hydrograph for return period 5, 10 and 25 has been done, the maximum flood for basin A with the mentioned return periods is equal to 0.84, 1.33 and 08.08 respectively. It is 2 cubic meters per second. For basin B, it is equal to 0.80, 1.27 and 2 cubic meters per second, respectively. Also, the maximum flood for basin C with the mentioned return periods is equal to 0.97, 1.55 and 2.24 cubic meters per second, respectively. The results of the flood hydrograph show that with the increase of the return period, the infiltration rate in the basin has decreased and the flood discharge has occurred earlier. Also, with the increase of the return period, the peak time of the hydrograph has decreased. Also, with the increase of the return period, the time of the base of the hydrograph and the subsidence time of the flood also increase. For flood zoning, the information obtained from the WMS model has been entered into the HEC-RAS model. According to the longitudinal profile and the 3-dimensional view of flood zoning, we can conclude that with the increase of the return period, the height of the water level in the longitudinal profile has increased. It is also clearly seen in the 3D view that the flood has covered more areas.