Landslide susceptibility mapping in order to control the agricultural land degradation (case study: Taleghan watershed)

Landslide is one of the most important factors in agricultural land degradation of Taleghan watershed. Landslide is a type of mass movement causing land degradation, accelerating soil erosion and delivering sediments to Taleghan dam, annually. Landslide susceptibility mapping is the first step for landslide hazard assessment and mitigation. The main aim of this study has been the landslide susceptibility mapping in order to identify areas prone to this phenomena and controlling land degradation in Taleghan watershed. For this purpose, thematic maps of effective factors on landslide, including elevation, slope angle, slope direction, slope shape, mean annual precipitation, mean annual temperature, lithology, land-use, vegetation density, distance from faults, distance from streams and distance from roads, are prepared by using geographical information system (GIS), topographic maps, satellite images and field survey. These factors were analyzed using multiple regression method to prepare the landslide susceptibility maps. The results showed that about 26 percent of watershed lands have been situated in high and very high susceptible areas most of which are in lithology gy2 classification (consisting of marl with high gypsum and salt), have rain-fed land-use and are located at 0-500 meter distances from the faults.