Spatial Analysis of Flood Risk in Tabas Watershed Using Satellite Images and Geographic Information System

Abstract

Among the natural phenomena, flood can be the biggest cause of damage, which always endangers the lives and properties of people. One of the management measures that can play a significant role in reducing damages is flood risk zoning. In this research, flood risk zoning has been done in the Tabas watershed. In general, the steps and this research were done in four stages. The effective criteria for creating the risk of flooding were identified, and the relevant layers were prepared. In the next step, mapping and standardization were done using fuzzy membership functions, then weighting of parameters was done using the hierarchical method, and finally overlapping of the layers was done using fuzzy operators. The criteria of distance from the river, slope, land use, rainfall, soil, digital elevation model and normalized difference vegetation index were respectively assigned the highest weight. Also, all fuzzy superposition operators (OR, AND, SUM, Product and Gamma) have been used for flood risk zoning. Among these operators, the 0.9 gamma operator shows the best and most reasonable result, so this map was chosen as the final flood risk zoning. In the final map, the total area of high-risk areas is 15432.13 ha. According to the final map obtained, areas with very high flood risk are located in the eastern part of the studied area. Areas with low risk are mostly located in the plains, valleys and depressions with less slope. The method used in this study can be used in other studies, such as zoning of earthquake risk potential, development zoning and spatial analysis of disease distribution.