Fuzzy flash flood risk and vulnerability assessment for the city of Sanandaj, Kurdistan Province, Iran

Flash floods are the most hazardous types of floods, specifically in urban areas, since they impose huge financial damages and tremendous life loss. A flood risk map is required to identify the most vulnerable areas of a city for better management of this phenomenon. This research aims at achieving the risk and vulnerability maps of the city of Sanandaj, Kurdistan Province, Iran, using the geographical information system and fuzzy analytic hierarchy process through the assessment of several conditioning factors. The parameters slope, elevation, profile curvature, drainage density, land use, and distance from waterways were applied to prepare a hazard of flood map of Sanandaj city. Also, effective information layers, including slope, elevation, permeability index, distance from hospitals, distance from fire stations, distance from trails, distance from refueling centers, distance from roads, and distance from historical monuments, were considered for designing a flood vulnerability map. By multiplying the hazard of flood occurrence map and the flood vulnerability map, the flood risk map is obtained. The designed flash flood risk map demonstrated that about 30% of the city's areas were classified as the most prone to flash floods. The results indicate that the flash flood is a serious concern in the city of Sanandaj, which should be considered by the city's officials and authorities. The designed flood risk map can be used as an appropriate management tool for reducing or avoiding flood risks.