Flood Zoning and Hydraulic Behavior Simulation Using HEC RAS in (GIS) Case Study: Maroon River - Southwestern Iran

The present project was designed with the aim of zoning the flood and determining the limits of the boundary and the boundaries of the Maroon River using the software (GIS) and HEC -RAS. The (HEC-HMS) model was used to simulate the flood hydrograph and determine the flood characteristics including peak discharge and runoff volume in Maroon watershed. Using (GIS) software, land surface maps, topography, curve numbers and elevation digital models were developed. In the next step, the profile of the river network and the geometric characteristics of the river were extracted using the (HEC-GeoRAS) toolbox. Finally, modeling and flood discharge estimation was done using (HEC-HMS) hydrologic model. And the results of the (HEC-HMS) model were combined with the geometric specification extracted from the (HEC-GeoRAS) model to the (HEC-RAS) model for the hydraulic modeling of the Maroon River. The final step is to transfer these results from the (HEC-RAS) hydraulic model to the Arc (GIS) software. At this stage, using available data, flood zoning was conducted for flood with a return period of 5, 10, 25 and 50 years. In this project, five flood events, which were well documented at the Tang-e-Takab Rain Station, were selected to calibrate and evaluate the model. The results of this study indicate that the flood area for 5, 10, 25 and 50 years return periods was 1265, 1651, 333 and 4450 ha, and the number of vulnerable villages Arrangements equal to 2.3, 4 and 9 villages are in jeopardy.