Flood Hazard Zoninig Using Multiple Criteria Decision Analysis System (Case Study: Sheytoor Watershed in Bafgh)

Today, one of the major problems of flood control projects is watershed prioritizing for resource allocation and structural and non-structural practices. Due to the lack of hydrometric stations in many watersheds, is difficult determining the participation of sub catchments to create flood. So study the affective factors in watersheds through models such as multi-criteria decision analyzing system (MCDAS) can help to determine the role of each sub catchment in creating flood. Despite the frequent occurrence of floods in Sector watershed, it has not any hydrometric station. The purpose of this study was to evaluate the potential of sub catchment in creating flood. In this study after providing digital layers of factors such as area, slope, main channel slope, drainage density, form factor, annual rainfall, land use and the infiltration of sub catchment, the AHP method was based to measure weight of each layer Finally, by applying weights and coefficients of each layer in MCDAS extension in ArcGIS, a combination map was produced. Pixel values of combination map can be varied from zero to one that it has much potential of flooding. According to the final map, the C'5 sub catchment has 0.79 value that has the greatest potential flood risk and it should be a priority for corrective practices. Next, C1 and C2 and C3 were at the high risk groups and C'7 and C'3 were at low risk group of flooding and C5 sub catchment with 0.15 value has the lowest risk of flooding in the region.