Geomorphological Risks and Their Impact on Transportation in the Zhelan Subdistrict, Sulaymaniyah Governorate

Abstract

The Current research examines the Geomorphological risks and their Impact on transportation routes in the Zhelan subdistrict, administratively affiliated with Sharbazher District in Sulaymaniyah Governorate, the area lies between the latitudes (35°41′00″ – 35°49′00″) north and the longitudes (45°36′00″ – 45°49′00″) east. It covers an area of approximately (203) km² and is situated at elevations ranging from (957.8 to 2000) meters above sea level. This research studies its natural properties and their role as a contributing factor in the variation of the geographical risks. These risks are erosion, destruction, and the cutting of roads by water channels, as well as landslides and rock mass movements. The studied area is classified into five categories of gully erosion according to the (Bergsma, 1983) equation. Subsequently, map matching was carried out using the (Maps Overlay) function in the ArcGIS program, which integrates five layers: geological structure, elevation, slope gradient, erosion, and vegetation cover. A transportation hazard map is generated, the map identified three levels of risk: low-risk areas, covering (17) km² or (8.4%) of the total area, with road lengths of (14) km, representing (15.8%) of the total road network; medium-risk areas, covering (118) km² or (58.1%) of the total area, with road lengths of (41) km, representing (45.3%) of the total road lengths; while high-risk areas covered (68) km², accounting for (33.5%) of the study area, with hazardous road lengths reaching (35) km, representing (38.7%) of the total road network length of (90) km.