Flood zoning using GIS tools and Hydraulic models in the Broudjerd Seilakhor floodplain, Iran

Flood is a complex natural disaster and destroying phenomenon that causes considerable annual damage. In addition, floodplain and lands alongside river beds are always in expose of flood hazards, while most of economic and social activities are conducted in these areas. Therefore, in these regions, flood zoning is necessary. Flood zoning maps, could be a suitable and lawful tool for determination of development strategies. In this research, the map of flood zoning with different return periods for a part of Broudjerd Seilakhor River, Iran was provided. Hydrological data and information were collected and analyzed. In addition, 32 cross sections were surveyed and floodplain characteristics (situation of bed, river banks, vegetation cover, etc) were noted. Flood routing by using Muskingum-Cunge method in different reaches was conducted. These data were used in the HEC-RAS model and its report was extracted. Topography map of this region was digitized using available contour maps. Next, Digital Elevation Model (DEM) and Triangular Irregular Network (TIN) using ArcView were created. Finally, flooding area and flow depth in different return periods were determined. The accuracy and precision of flooding maps were evaluated by comparison with information and local investigations. The results show that by considering the HEC-RAS limitations (reach shortness), the final flooding maps are accurate enough for the aim of this kind of study.

Keywords:

Flood , zoning , HEC-RAS , ArcView , Broudjerd , Seilakhor