Susceptibility to flooding in the Razavar Watershed using analytical hierarchy process method

In Iran, the vast floods are occurring frequently those are due to huge area, climate changes, land use change and temporal and spatial variations of precipitation. The current research mainly aims to assess Analytical Hierarchy Process (AHP) method to provide flood susceptibility map. In this study, different factors, e. g. elevation classes, the percentage of slope, land curvature, distance from the river, geology, land use types, curve number and soil hydrological groups are used in the Razavar watershed in Kermanshah province. The raster maps of these layers were provided by using ArcGIS10. 1 and SAGA GIS2. The flooding probability of each class for different factors as well as the importance of each factor in comparison with other factors was evaluated according to the expert opinions, then the related weights were calculated in the expert choice software. Furthermore, the obtained weights of each class/factor were applied to every layer using Geographic Information Systems (GIS) to provide flood susceptibility map. The results showed that the percentage of the slope had the highest effects on the flood, and also distance from the river and the elevation classes are in the next priorities. The lowest factor in the flood is related to curve number. Moreover, the results indicated that about 48. 5% and 30. 9% of the study area were recognized with high sensitivity and low/very low sensitivity, respectively.