Flood hazard potential zonation of Baghan watershed using fuzzy analytic hierarchy process method (FAHP)

The aim of this research is flooded hazard potential zonation of Baghan watershed using geographic information system (GIS) and Fuzzy analytic hierarchy process method (FAHP). After identifying effective factors in flood hazard (slope، digital elevation model، permeability، lithology، infiltration، land use، vegetation cover density، precipitation، network drainage density، distance from the stream)، criteria and subcriteria weight were calculated using pairwise comparisons and experts'' comments as well as FAHP. Watershed flood hazard potential was zoned and finally، the watershed was categorized into five classes based on flood hazard risk using a fuzzy gamma operator. The results of flood hazard risk zonation indicate that classes 1، 2 and 3 are generally located in mountainous areas and include about 22% (203 km2) of the region and so it can be concluded that، the 22% part of runoff yield، watershed management projects in this region are in priority. Classes 4 and 5 have less flood hazard potential in comparison to class 1، 2 and 3 and are located in slopes and taluses in mountainous areas and cover about 78% (706 km2) of the region.