Flood Hazard Assessment Using Geospatial Information System in Tajan Basin

In this study, it is attempted to provide a proper assessment of flood status and flood risk for Tajan watershed. In this regard, by preparing flood hazard zoning maps and flood sensitivity analysis for the basin, susceptible areas have been identified and the extent of the hazard has been assessed for the basin. To this end, a fuzzy hierarchical fuzzy analysis (F-AHP) integrated model is used to prioritize, identify factors influencing flood events (including geological, climate, human factors, etc.) and determine the extent of impact of each. Flood assessment indices (including flow velocity, flow depth, mean precipitation, evaporation, slope aspect, drift pattern, flood plain, road network and land cover) were used. This information was transferred to the GIS environment after fuzzy evaluation in MATLAB and fuzzified/defuzzified index maps of the area were prepared. The goal of this work is to increase accuracy as well as integrate fuzzy models. These maps are used to identify flood sensitive areas (hazard maps) and hazard zoning (in 5 high-risk to low-risk groups). Based on the results of the hazard assessment, it has been identified that the most important concentration of flood sensitive areas in the main river is in relation to other parts and in the delta. Also, according to the drainage pattern of the region, especially in the eastern part of the basin, it has been determined that these areas also have a high sensitivity to flooding.