Efficiency of Victor model in landslide risk zoning in the watershed of Galal Dam in Ilam Province

Landslides are one of the natural hazards that are always associated with financial and human losses. Understanding the causes and its different types is very important for us. Identifying and determining sensitive and landslide prone areas can prevent damage and provide a basis for the implementation of slope stabilization projects. In the present study, landslide risk assessment in the watershed of Galal Dam in Ilam province has been performed using Vickor multi-criteria decision making method. Accordingly, among various factors, 8 geological parameters, altitude, slope, precipitation, distance from the fault, distance from the waterway, distance from the road and land use as the most important effective parameters in the occurrence of landslides in the region, have been identified. Then, the significance coefficient of each of the effective factors in the occurrence of landslide was obtained by the method of hierarchical analysis of systems in which the geological criteria slope and precipitation gained the highest coefficient of importance. Then, based on Vickor optimization algorithm, the degree of usefulness and regret of selecting the best options (sub-basins) is determined, and finally by calculating the amount of Vickor optimal index (Q), sub-basins according to the degree of landslide sensitivity in three quality classes of sensitivity Low, medium and high susceptibility were classified. The results showed that the sub-basins of Ban Sohan, Palkaneh and Haji Bakhtiar have the highest susceptibility and the sub-basins of Chegan, Dard Mirnaser and Chegah have the lowest susceptibility to landslides. From the adaptation of zoning maps and landslides in the region, the accuracy of the map can be understood and it was also found that the Vickor model used in this study is a very suitable method for zoning the risk of landslides in the study basin.