Development of a landslide management plan under normal and critical scenarios for Ziarat Watershed, Golestan Province

Destructive natural hazards are causing considerable damage in several parts of Iran. Identification of Hazard-prone areas is the key to developing effective vulnerability reduction measures regarding probable hazards. Landslide hazard and risk zonation is one of initial stages in management plans of landslide to reduce loss of life, human sufferings and economic losses. In this study, the AHP-weighted bivariate (density-area) method was used for landslide hazard mapping in the Ziarat Watershed, Golestan Province. Landslide risk zoning was implemented considering the outcomes of landslide hazard mapping, elements at risk, and vulnerability degree of according to the general risk equation. The landslide management plan was developed using the multi-criteria evaluation technique for normal and critical scenarios in the study area. The results show that 27.45% and 4.37% of the study area was determined as high and very-high hazard classes, respectively. In addition, 7.86% of the watershed area located in low risk class, and 25.69% assigned as high and very high risk class. The total estimated economic losses were around 2251405 million Iranian Rials. Considering the application of management scenario in the normal condition, 3.2% of the area requires a strategy of risk avoidance and control measures are needed for 50.8% of the area (in the forest and pasture land-uses). While in the critical scenario, 44.3% of the study area need to avoiding the risk and control measures should be employed in the 29% of the area (both located middle and adjacent to the watershed outlet) with high human activities.