Use of Digital Elevation Model for Study of Drainage Morphometry and Identification Stability and Saturation Zones in Relations to Landslide Assessments in Parts of the Shahbazan Area, SW Iran

Abstract

The south-western trans Iranian railway line connecting Tehran, Iran to Khoramshahr in the southwest crosses the great Zagros range. One of the localities on this line is the Shahbazan railway station. Shahbazan station is located in the Alwar section of the central Zagros belt in the southwest of Iran. Complex geological-geomorphological activities have created an immature and rugged landscape which in turn imposes various natural hazards (landslide, erosion and flash flooding) to both people and the railway infra-strucutre. In order to address these problems on a regional scale, a digital elevation model (DEM) was used in conjunction with selected field visits during which various parameters related to lithology (dip, strike and rock types), structures (joints, fracturres, faults and folds), soil types, landuse and land cover were obsereved and measured. For the creation of a DEM, a digital topographic map prepared by the Iranian Surveying Organization was used. The DEM was computed using x, y, z attributes in text format. The methodology includes an interactive visual calibration that adjusts parameters while referring to observed landslides. Based on field data collected, the DEM was calibrated to generate stability zone map and saturation zone map of the study area which address to natural hazards like landslide. The analyses of drainage morphometery, relief and saturation maps reveals zones of stability-instability and saturation within the study area which are in harmony with landslide and rock fall zones. However, the study also indicates that the DEM provides a useful tool for rapid evaluation of natural hazards and mapping of large areas with less time and good results.