Evaluating and zoning flooding on a temporal and spatial scale (Study Area: Gorgan River Watershed in Golestan Province)

Accurate using of land and water is the effective step in controlling the erosion, soil ruin and developing the agriculture. Flood has been one of the existed phenomenon in the nature which human has been seen since the past. Iran, because of wide area, different climates and change landuses in most watersheds, has increasingly experienced severe floods. Feasibility study of flood and evaluating the sensitive place prone to flood is the main step for controlling and managing the flood and utilizing it. Gorganroud Basin in Golestan province, that is one of the areas which has experienced several floods during the last years, and because of mismanagement, it has caused to several life and property losses to the residents of this area. In this study After identifying effective factors in flood hazard (slope, digital elevation model, permeability, Soil hydrologic group, Runoff potential, Curve number, distance from the stream, land use, vegetation cover density), criteria and subcriteria weight were calculated using pairwise comparisons and experts’ comments as well as ANP. Watershed flood hazard potential was zoned and finally, the watershed was categorized into five classes based on flood hazard risk. The results of flood hazard risk zonation indicate that classes 1 and 2 (very high and high risk) are generally located in North, North East and South East areas and include about 20% of the region. the results of the study were supplied for recognizing the area with high possibility of flooding in Kaleybar Chay basin and the provided maps will be used in executive organizations (governorate, natural resources, …) for logistics planning and controlling the flood.